diff --git a/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Exception.php b/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Exception.php
new file mode 100644
index 00000000000..238de08835a
--- /dev/null
+++ b/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Exception.php
@@ -0,0 +1,30 @@
+<?php
+/**
+ * The exception marker for data specific Horde_Kolab_Storage errors.
+ *
+ * PHP version 5
+ *
+ * @category Kolab
+ * @package  Kolab_Storage
+ * @author   Gunnar Wrobel <wrobel@pardus.de>
+ * @license  http://www.horde.org/licenses/lgpl21 LGPL 2.1
+ * @link     http://pear.horde.org/index.php?package=Kolab_Storage
+ */
+
+/**
+ * The exception marker for data specific Horde_Kolab_Storage errors.
+ *
+ * Copyright 2012 Horde LLC (http://www.horde.org/)
+ *
+ * See the enclosed file COPYING for license information (LGPL). If you
+ * did not receive this file, see http://www.horde.org/licenses/lgpl21.
+ *
+ * @category Kolab
+ * @package  Kolab_Storage
+ * @author   Gunnar Wrobel <wrobel@pardus.de>
+ * @license  http://www.horde.org/licenses/lgpl21 LGPL 2.1
+ * @link     http://pear.horde.org/index.php?package=Kolab_Storage
+ */
+class Horde_Kolab_Storage_Data_Exception extends Horde_Exception_Wrapped
+{
+}
diff --git a/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Format/Mime.php b/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Format/Mime.php
index eecbf9a5e6f..271d8bee620 100644
--- a/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Format/Mime.php
+++ b/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Format/Mime.php
@@ -240,17 +240,19 @@ public function createKolabPart($object, array $options)
         $kolab = new Horde_Mime_Part();
         $kolab->setType($this->getMimeType($options['type']));
         if (empty($options['raw'])) {
+            $format = new Horde_Kolab_Storage_Data_Object_Content(
+                $this->_factory->createFormat(
+                    'Xml', $options['type'], $options['version']
+                )
+            );
             if (isset($options['previous'])) {
-                $previous = array('previous' => $options['previous']);
+                $content = $format->modify($object, $options['previous']);
             } else {
-                $previous = array();
+                $content = $format->create($object);
             }
             try {
                 $kolab->setContents(
-                    $this->_factory->createFormat(
-                        'Xml', $options['type'], $options['version']
-                    )->save($object, $previous),
-                    array('encoding' => 'quoted-printable')
+                    $content, array('encoding' => 'quoted-printable')
                 );
             } catch (Horde_Kolab_Format_Exception $e) {
                 throw new Horde_Kolab_Storage_Exception(
diff --git a/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Object/Content.php b/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Object/Content.php
new file mode 100644
index 00000000000..0b2a8e32471
--- /dev/null
+++ b/framework/Kolab_Storage/lib/Horde/Kolab/Storage/Data/Object/Content.php
@@ -0,0 +1,85 @@
+<?php
+/**
+ * Generates the core Kolab content.
+ *
+ * PHP version 5
+ *
+ * @category Kolab
+ * @package  Kolab_Storage
+ * @author   Gunnar Wrobel <wrobel@pardus.de>
+ * @license  http://www.horde.org/licenses/lgpl21 LGPL 2.1
+ * @link     http://pear.horde.org/index.php?package=Kolab_Storage
+ */
+
+/**
+ * Generates the core Kolab content.
+ *
+ * Copyright 2011-2012 Horde LLC (http://www.horde.org/)
+ *
+ * See the enclosed file COPYING for license information (LGPL). If you
+ * did not receive this file, see http://www.horde.org/licenses/lgpl21.
+ *
+ * @category Kolab
+ * @package  Kolab_Storage
+ * @author   Gunnar Wrobel <wrobel@pardus.de>
+ * @license  http://www.horde.org/licenses/lgpl21 LGPL 2.1
+ * @link     http://pear.horde.org/index.php?package=Kolab_Storage
+ */
+class Horde_Kolab_Storage_Data_Object_Content
+{
+    /**
+     * Kolab format handler.
+     *
+     * @var Horde_Kolab_Format
+     */
+    private $_format;
+
+    /**
+     * Constructor.
+     *
+     * @param Horde_Kolab_Format $format The Kolab format handler.
+     */
+    public function __construct(Horde_Kolab_Format $format)
+    {
+        $this->_format = $format;
+    }
+
+    /**
+     * Create the Kolab content as a string.
+     *
+     * @param array $object The object data.
+     *
+     * @return string The Kolab content.
+     */
+    public function create(array $object)
+    {
+        try {
+            return $this->_format->save($object);
+        } catch (Horde_Kolab_Format_Exception $e) {
+            throw new Horde_Kolab_Storage_Data_Exception(
+                'Failed saving Kolab object!', 0, $e
+            );
+        }
+    }
+
+    /**
+     * Modify a previous Kolab object.
+     *
+     * @param array  $object   The new object data.
+     * @param string $previous The previous data.
+     *
+     * @return string The new Kolab content.
+     */
+    public function modify(array $object, $previous)
+    {
+        try {
+            return $this->_format->save(
+                $object, array('previous' => $previous)
+            );
+        } catch (Horde_Kolab_Format_Exception $e) {
+            throw new Horde_Kolab_Storage_Data_Exception(
+                'Failed saving Kolab object!', 0, $e
+            );
+        }
+    }
+}
\ No newline at end of file
diff --git a/framework/Kolab_Storage/test/Horde/Kolab/Storage/Unit/Data/Object/ContentTest.php b/framework/Kolab_Storage/test/Horde/Kolab/Storage/Unit/Data/Object/ContentTest.php
new file mode 100644
index 00000000000..9ef5095e359
--- /dev/null
+++ b/framework/Kolab_Storage/test/Horde/Kolab/Storage/Unit/Data/Object/ContentTest.php
@@ -0,0 +1,93 @@
+<?php
+/**
+ * Test the Kolab content handler.
+ *
+ * PHP version 5
+ *
+ * @category   Kolab
+ * @package    Kolab_Storage
+ * @subpackage UnitTests
+ * @author     Gunnar Wrobel <wrobel@pardus.de>
+ * @license    http://www.horde.org/licenses/lgpl21 LGPL 2.1
+ * @link       http://pear.horde.org/index.php?package=Kolab_Storage
+ */
+
+/**
+ * Prepare the test setup.
+ */
+require_once __DIR__ . '/../../../Autoload.php';
+
+/**
+ * Test the Kolab content handler.
+ *
+ * Copyright 2011-2012 Horde LLC (http://www.horde.org/)
+ *
+ * See the enclosed file COPYING for license information (LGPL). If you
+ * did not receive this file, see http://www.horde.org/licenses/lgpl21.
+ *
+ * @category   Kolab
+ * @package    Kolab_Storage
+ * @subpackage UnitTests
+ * @author     Gunnar Wrobel <wrobel@pardus.de>
+ * @license    http://www.horde.org/licenses/lgpl21 LGPL 2.1
+ * @link       http://pear.horde.org/index.php?package=Kolab_Storage
+ */
+class Horde_Kolab_Storage_Unit_Data_Object_ContentTest
+extends PHPUnit_Framework_TestCase
+{
+    public function testCreate()
+    {
+        $format = $this->getMock('Horde_Kolab_Format');
+        $format->expects($this->once())
+            ->method('save')
+            ->with(array('foo' => 'foo'))
+            ->will($this->returnValue('<event/>'));
+        $content = new Horde_Kolab_Storage_Data_Object_Content($format);
+        $this->assertEquals(
+            '<event/>', $content->create(array('foo' => 'foo'))
+        );
+    }
+
+    /**
+     * @expectedException Horde_Kolab_Storage_Data_Exception
+     */
+    public function testCreateWithException()
+    {
+        $format = $this->getMock('Horde_Kolab_Format');
+        $format->expects($this->once())
+            ->method('save')
+            ->with(array('foo' => 'foo'))
+            ->will($this->throwException(new Horde_Kolab_Format_Exception()));
+        $content = new Horde_Kolab_Storage_Data_Object_Content($format);
+        $content->create(array('foo' => 'foo'));
+    }
+
+    public function testModify()
+    {
+        $format = $this->getMock('Horde_Kolab_Format');
+        $format->expects($this->once())
+            ->method('save')
+            ->with(array('foo' => 'foo'), array('previous' => '<event/>'))
+            ->will($this->returnValue('<event><modified/></event>'));
+        $content = new Horde_Kolab_Storage_Data_Object_Content($format);
+        $this->assertEquals(
+            '<event><modified/></event>',
+            $content->modify(array('foo' => 'foo'), '<event/>')
+        );
+    }
+
+    /**
+     * @expectedException Horde_Kolab_Storage_Data_Exception
+     */
+    public function testModifyWithException()
+    {
+        $format = $this->getMock('Horde_Kolab_Format');
+        $format->expects($this->once())
+            ->method('save')
+            ->with(array('foo' => 'foo'), array('previous' => '<event/>'))
+            ->will($this->throwException(new Horde_Kolab_Format_Exception()));
+        $content = new Horde_Kolab_Storage_Data_Object_Content($format);
+        $content->modify(array('foo' => 'foo'), '<event/>');
+    }
+
+}