diff --git a/lib/DoctrineExtensions/Workflow/DefinitionStorage.php b/lib/DoctrineExtensions/Workflow/DefinitionStorage.php
index 5ff9d67..f377966 100644
--- a/lib/DoctrineExtensions/Workflow/DefinitionStorage.php
+++ b/lib/DoctrineExtensions/Workflow/DefinitionStorage.php
@@ -133,17 +133,12 @@ protected function loadWorkflow($workflowId, $workflowName, $workflowVersion)
         foreach ( $result as $node ) {
             $node = array_change_key_case($node, \CASE_LOWER);
 
-            $configuration = \ezcWorkflowDatabaseUtil::unserialize(
-                    $node['node_configuration'], null
-            );
+            $configuration = $this->options->getSerializer()->unserialize($node['node_configuration'], null);
 
             if ( is_null( $configuration ) ) {
                 $configuration = \ezcWorkflowUtil::getDefaultConfiguration( $node['node_class'] );
             }
 
-            /*$nodes[$node['node_id']] = new $node['node_class'](
-                    $configuration
-            );*/
             $nodes[$node['node_id']] = $this->options->getNodeFactory()->createNode($node['node_class'], $configuration);
 
             if ($nodes[$node['node_id']] instanceof \ezcWorkflowNodeFinally &&
@@ -264,7 +259,7 @@ public function save( \ezcWorkflow $workflow )
                 $this->conn->insert($this->options->nodeTable(), array(
                     'workflow_id' => (int)$workflow->id,
                     'node_class' => get_class($node),
-                    'node_configuration' => \ezcWorkflowDatabaseUtil::serialize( $node->getConfiguration() ),
+                    'node_configuration' => $this->options->getSerializer()->serialize( $node->getConfiguration() ),
                 ));
 
                 $nodeId = $this->conn->lastInsertId();
diff --git a/lib/DoctrineExtensions/Workflow/DoctrineExecution.php b/lib/DoctrineExtensions/Workflow/DoctrineExecution.php
index 7904589..eed66bd 100644
--- a/lib/DoctrineExtensions/Workflow/DoctrineExecution.php
+++ b/lib/DoctrineExtensions/Workflow/DoctrineExecution.php
@@ -50,15 +50,6 @@ protected function doStart($parentId)
         $platform = $this->conn->getDatabasePlatform();
 
         $variables = $this->variables;
-        $executionEntityName = null;
-        $executionEntityId = null;
-
-        if (isset($variables['entityName'])) {
-            $executionEntityName = $variables['entityName'];
-        }
-        if (isset($variables['entityId'])) {
-            $executionEntityId = $variables['entityId'];
-        }
 
         $executionNextPollDate = null;
         if (isset($variables['batchWaitInterval'])) {
@@ -67,22 +58,22 @@ protected function doStart($parentId)
             }
 
             $executionNextPollDate = new \DateTime("now");
-            $executionNextPollDate->add($variables['waitInterval']);
+            $executionNextPollDate->add($variables['batchWaitInterval']);
             $executionNextPollDate = $executionNextPollDate->format($platform->getDateTimeFormatString());
         }
 
+        $serializer = $this->options->getSerializer();
+
         $now = new \DateTime("now");
         $data = array(
-            'workflow_id' => (int)$this->workflow->id,
-            'execution_parent' => $parentId,
-            'execution_started' => $now->format($platform->getDateTimeFormatString()),
-            'execution_variables' => \ezcWorkflowDatabaseUtil::serialize($variables),
-            'execution_waiting_for' => \ezcWorkflowDatabaseUtil::serialize($this->waitingFor),
-            'execution_threads' => \ezcWorkflowDatabaseUtil::serialize($this->threads),
-            'execution_next_thread_id' => (int)$this->nextThreadId,
-            'execution_entity_name' => $executionEntityName,
-            'execution_entity_id' => $executionEntityId,
-            'execution_next_poll_date' => $executionNextPollDate,
+            'workflow_id'               => (int)$this->workflow->id,
+            'execution_parent'          => $parentId,
+            'execution_started'         => $now->format($platform->getDateTimeFormatString()),
+            'execution_variables'       => $serializer->serialize($variables),
+            'execution_waiting_for'     => $serializer->serialize($this->waitingFor),
+            'execution_threads'         => $serializer->serialize($this->threads),
+            'execution_next_thread_id'  => (int)$this->nextThreadId,
+            'execution_next_poll_date'  => $executionNextPollDate,
         );
         $this->conn->insert($this->options->executionTable(), $data);
 
@@ -149,14 +140,16 @@ protected function doSuspend()
             $executionNextPollDate = $executionNextPollDate->format($platform->getDateTimeFormatString());
         }
 
+        $serializer = $this->options->getSerializer();
+
         $now = new \DateTime("now");
         $data = array(
-            'execution_suspended' => $now->format($platform->getDateTimeFormatString()),
-            'execution_variables' => \ezcWorkflowDatabaseUtil::serialize($variables),
-            'execution_waiting_for' => \ezcWorkflowDatabaseUtil::serialize($this->waitingFor),
-            'execution_threads' => \ezcWorkflowDatabaseUtil::serialize($this->threads),
-            'execution_next_thread_id' => (int)$this->nextThreadId,
-            'execution_next_poll_date' => $executionNextPollDate,
+            'execution_suspended'       => $now->format($platform->getDateTimeFormatString()),
+            'execution_variables'       => $serializer->serialize($variables),
+            'execution_waiting_for'     => $serializer->serialize($this->waitingFor),
+            'execution_threads'         => $serializer->serialize($this->threads),
+            'execution_next_thread_id'  => (int)$this->nextThreadId,
+            'execution_next_poll_date'  => $executionNextPollDate,
         );
 
         $this->cleanUpExecutionStateTable();
@@ -164,11 +157,11 @@ protected function doSuspend()
 
         foreach ($this->activatedNodes AS $node) {
             $data = array(
-                'execution_id' => (int)$this->id,
-                'node_id' => (int)$node->getId(),
-                'node_state' => \ezcWorkflowDatabaseUtil::serialize( $node->getState() ),
-                'node_activated_from' => \ezcWorkflowDatabaseUtil::serialize( $node->getActivatedFrom() ),
-                'node_thread_id' => $node->getThreadId(),
+                'execution_id'          => (int)$this->id,
+                'node_id'               => (int)$node->getId(),
+                'node_state'            => $serializer->serialize( $node->getState() ),
+                'node_activated_from'   => $serializer->serialize( $node->getActivatedFrom() ),
+                'node_thread_id'        => $node->getThreadId(),
             );
             $this->conn->insert($this->options->executionStateTable(), $data);
         }
@@ -198,9 +191,11 @@ protected function loadExecution($executionId)
         $this->id = (int)$execution['execution_id'];
         $this->nextThreadId = $execution['execution_next_thread_id'];
 
-        $this->variables = \ezcWorkflowDatabaseUtil::unserialize($execution['execution_variables']);
-        $this->waitingFor = \ezcWorkflowDatabaseUtil::unserialize($execution['execution_waiting_for']);
-        $this->threads = \ezcWorkflowDatabaseUtil::unserialize($execution['execution_threads']);
+        $serializer = $this->options->getSerializer();
+
+        $this->variables    = $serializer->unserialize($execution['execution_variables']);
+        $this->waitingFor   = $serializer->unserialize($execution['execution_waiting_for']);
+        $this->threads      = $serializer->unserialize($execution['execution_threads']);
 
         $this->workflow = $this->definitionStorage->loadById($execution['workflow_id']);
 
@@ -216,9 +211,9 @@ protected function loadExecution($executionId)
             $row = array_change_key_case($row, \CASE_LOWER);
             
             $active[$row['node_id']] = array(
-                'activated_from' => \ezcWorkflowDatabaseUtil::unserialize($row['node_activated_from']),
-                'state' => \ezcWorkflowDatabaseUtil::unserialize($row['node_state'], null),
-                'thread_id' => $row['node_thread_id'],
+                'activated_from'    => $serializer->unserialize($row['node_activated_from']),
+                'state'             => $serializer->unserialize($row['node_state'], null),
+                'thread_id'         => $row['node_thread_id'],
             );
         }
 
diff --git a/lib/DoctrineExtensions/Workflow/SchemaBuilder.php b/lib/DoctrineExtensions/Workflow/SchemaBuilder.php
index 0c891b4..7e1ee5d 100644
--- a/lib/DoctrineExtensions/Workflow/SchemaBuilder.php
+++ b/lib/DoctrineExtensions/Workflow/SchemaBuilder.php
@@ -100,8 +100,6 @@ public function getWorkflowSchema(WorkflowOptions $options)
         $executionTable->addColumn('execution_threads', 'text', array('notnull' => false, "length" => null));
         $executionTable->addColumn('execution_next_thread_id', 'integer');
         $executionTable->addColumn('execution_next_poll_date', 'datetime', array('notnull' => false));
-        $executionTable->addColumn('execution_entity_name', 'string', array('notnull' => false));
-        $executionTable->addColumn('execution_entity_id', 'integer', array('notnull' => false));
 
         $executionTable->setPrimaryKey(array('execution_id'));
         $executionTable->addIndex(array('execution_parent'));
diff --git a/lib/DoctrineExtensions/Workflow/Util/Serialize/JsonSerializer.php b/lib/DoctrineExtensions/Workflow/Util/Serialize/JsonSerializer.php
deleted file mode 100644
index 5d7c89a..0000000
--- a/lib/DoctrineExtensions/Workflow/Util/Serialize/JsonSerializer.php
+++ /dev/null
@@ -1,33 +0,0 @@
-<?php
-/**
- * Doctrine Workflow
- *
- * LICENSE
- *
- * This source file is subject to the new BSD license that is bundled
- * with this package in the file LICENSE.txt.
- * If you did not receive a copy of the license and are unable to
- * obtain it through the world-wide-web, please send an email
- * to kontakt@beberlei.de so I can send you a copy immediately.
- */
-
-namespace DoctrineExtensions\Workflow\Util\Serialize;
-
-class JsonSerializer implements Serializer
-{
-    public function serialize($value) {
-        if ($value === null || (is_array($value) && count($value) == 0)) {
-            return '';
-        }
-
-        return json_encode($value);
-    }
-
-    public function unserialize($value, $defaultValue = array())
-    {
-        if (!empty($value)) {
-            return json_decode($value, true);
-        }
-        return $defaultValue;
-    }
-}
\ No newline at end of file
diff --git a/tests/DoctrineExtensions/Workflow/DefinitionStorageTest.php b/tests/DoctrineExtensions/Workflow/DefinitionStorageTest.php
index 5a6e0bf..9563c73 100644
--- a/tests/DoctrineExtensions/Workflow/DefinitionStorageTest.php
+++ b/tests/DoctrineExtensions/Workflow/DefinitionStorageTest.php
@@ -7,10 +7,18 @@ class DefinitionStorageTest extends \PHPUnit_Framework_TestCase
     private $conn;
     private $options;
 
+    public function createSerializer()
+    {
+        if (isset($GLOBALS['DOCTRINE_WORKFLOW_SERIALIZER_IMPL'])) {
+            return new $GLOBALS['DOCTRINE_WORKFLOW_SERIALIZER_IMPL']();
+        }
+        return null;
+    }
+
     public function setUp()
     {
         $this->conn = \DoctrineExtensions\Workflow\TestHelper::getConnection();
-        $this->options = new WorkflowOptions('test_');
+        $this->options = new WorkflowOptions('test_', null, null, $this->createSerializer());
         TestHelper::createSchema($this->options);
     }
 
diff --git a/tests/DoctrineExtensions/Workflow/DoctrineExecutionTest.php b/tests/DoctrineExtensions/Workflow/DoctrineExecutionTest.php
index 37af423..23c086b 100644
--- a/tests/DoctrineExtensions/Workflow/DoctrineExecutionTest.php
+++ b/tests/DoctrineExtensions/Workflow/DoctrineExecutionTest.php
@@ -26,10 +26,18 @@ class DoctrineExecutionTest extends \PHPUnit_Framework_TestCase
      */
     private $storage;
 
+    public function createSerializer()
+    {
+        if (isset($GLOBALS['DOCTRINE_WORKFLOW_SERIALIZER_IMPL'])) {
+            return new $GLOBALS['DOCTRINE_WORKFLOW_SERIALIZER_IMPL']();
+        }
+        return null;
+    }
+
     public function setUp()
     {
         $this->conn = \DoctrineExtensions\Workflow\TestHelper::getConnection();
-        $this->options = new WorkflowOptions('test_');
+        $this->options = new WorkflowOptions('test_', null, null, $this->createSerializer());
         TestHelper::createSchema($this->options);
         $this->storage = new DefinitionStorage($this->conn, $this->options);
     }
diff --git a/tests/DoctrineExtensions/Workflow/TestHelper.php b/tests/DoctrineExtensions/Workflow/TestHelper.php
index 0eb8d6c..0d56258 100644
--- a/tests/DoctrineExtensions/Workflow/TestHelper.php
+++ b/tests/DoctrineExtensions/Workflow/TestHelper.php
@@ -16,15 +16,30 @@ static public function createSchema(WorkflowOptions $options)
     {
         $conn = self::getConnection();
 
-        $schemaBuilder = new SchemaBuilder($conn);
-        try {
-            $schemaBuilder->dropWorkflowSchema($options);
-        } catch(\PDOException $e) {
-
+        if (!isset(self::$schema[$options->getTablePrefix()])) {
+            $schemaBuilder = new SchemaBuilder($conn);
+            try {
+                $schemaBuilder->dropWorkflowSchema($options);
+            } catch(\PDOException $e) {
+
+            }
+            $schemaBuilder->createWorkflowSchema($options);
+            
+            self::$schema[$options->getTablePrefix()] = true;
         }
-        $schemaBuilder->createWorkflowSchema($options);
 
-        self::$schema[$options->getTablePrefix()] = true;
+        $platform = $conn->getDatabasePlatform();
+        $tables = array(
+            $options->executionStateTable(),
+            $options->executionTable(),
+            $options->variableHandlerTable(),
+            $options->nodeConnectionTable(),
+            $options->nodeTable(),
+            $options->workflowTable(),
+        );
+        foreach ($tables AS $table) {
+            $conn->executeUpdate($platform->getTruncateTableSQL($table));
+        }
     }
 
     static public function getConnection()
diff --git a/tests/DoctrineExtensions/Workflow/Util/SerializerTest.php b/tests/DoctrineExtensions/Workflow/Util/SerializerTest.php
index 4fe4d5d..bbee9d6 100644
--- a/tests/DoctrineExtensions/Workflow/Util/SerializerTest.php
+++ b/tests/DoctrineExtensions/Workflow/Util/SerializerTest.php
@@ -17,6 +17,8 @@ public static function dataSerialize()
             array(array('foo' => 'bar'),    array('foo' => 'bar'),      array()),
             array(array('foo' => 'bar'),    array('foo' => 'bar'),      null),
             array(array('c' => "\xc9\x80"), array('c' => "\xc9\x80"),   null),
+            // empty object instances exist in ezcWorkflow!!
+            array(array('c' => new \stdClass()), array('c' => new \stdClass()), null),
         );
     }
 
@@ -41,13 +43,4 @@ public function testWbbxSerializer($value, $expectedValue, $defaultValue)
         $z = new WddxSerializer();
         $this->assertEquals($expectedValue, $z->unserialize($z->serialize($value), $defaultValue));
     }
-
-    /**
-     * @dataProvider dataSerialize
-     */
-    public function testJsonSerializer($value, $expectedValue, $defaultValue)
-    {
-        $z = new JsonSerializer();
-        $this->assertEquals($expectedValue, $z->unserialize($z->serialize($value), $defaultValue));
-    }
 }
diff --git a/tests/phpunit.dist.xml b/tests/phpunit.dist.xml
index bec3d8f..e5c1723 100644
--- a/tests/phpunit.dist.xml
+++ b/tests/phpunit.dist.xml
@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit bootstrap="./DoctrineExtensions/Workflow/TestHelper.php">
     <php>
+        <var name="DOCTRINE_WORKFLOW_SERIALIZER_IMPL" value="DoctrineExtensions\Workflow\Util\Serialize\ZetaSerializer" />
         <var name="doctrine2-common-path" value="" />
         <var name="doctrine2-dbal-path" value="" />
         <var name="ezc-base-file" value="" />