diff --git a/lib/simple_mapper/attribute/pattern.rb b/lib/simple_mapper/attribute/pattern.rb
index 5f2ee6d..60df818 100644
--- a/lib/simple_mapper/attribute/pattern.rb
+++ b/lib/simple_mapper/attribute/pattern.rb
@@ -12,7 +12,7 @@ def pattern=(value)
   end
 
   def source_value(object)
-    object.simple_mapper_source.inject({}) do |hash, keyval|
+    object.simple_mapper_source.inject(new_collection) do |hash, keyval|
       hash[from_simple_key(keyval[0])] = keyval[1] if pattern.match(keyval[0].to_s)
       hash
     end
diff --git a/test/unit/attribute_pattern_test.rb b/test/unit/attribute_pattern_test.rb
index 8585222..faa47bd 100644
--- a/test/unit/attribute_pattern_test.rb
+++ b/test/unit/attribute_pattern_test.rb
@@ -54,6 +54,11 @@ class SimpleMapperAttributePatternTest < Test::Unit::TestCase
           assert_equal({}, @instance.source_value(@object))
         end
 
+        should 'get its container value from :new_collection' do
+          @instance.expects(:new_collection).returns(container = stub('container'))
+          assert_equal(container, @instance.source_value(@object))
+        end
+
         should 'return hash with key/value pairs for only the keys matching pattern' do
           expected = {:a => 'A', :abc => 'ABC', :aarp => 'AARP'}
           @source_values.merge! expected