diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index fbcd486..e672d80 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -132,7 +132,6 @@ class Configuration implements ConfigurationInterface
                 ->arrayNode('indexes')
                     ->useAttributeAsKey('name')
                     ->prototype('array')
-                        ->performNoDeepMerging()
                         ->children()
                             ->scalarNode('index_name')->end()
                             ->scalarNode('client')->end()
@@ -301,6 +300,8 @@ class Configuration implements ConfigurationInterface
                 ->append($this->getRoutingNode())
                 ->append($this->getParentNode())
                 ->append($this->getAllNode())
+                ->append($this->getTimestampNode())
+                ->append($this->getTtlNode())
             ->end()
         ;
 
@@ -401,7 +402,8 @@ class Configuration implements ConfigurationInterface
                     ->scalarNode('identifier')->defaultValue('id')->end()
                 ->end()
             ->end()
-            ->scalarNode('format')->end();
+            ->scalarNode('format')->end()
+            ->scalarNode('similarity')->end();
         ;
 
         if (isset($nestings['fields'])) {
@@ -649,4 +651,45 @@ class Configuration implements ConfigurationInterface
 
         return $node;
     }
+
+    /**
+     * Returns the array node used for "_timestamp"
+     */
+    protected function getTimestampNode()
+    {
+        $builder = new TreeBuilder();
+        $node = $builder->root('_timestamp');
+
+        $node
+            ->children()
+            ->scalarNode('enabled')->defaultValue(true)->end()
+            ->scalarNode('path')->end()
+            ->scalarNode('format')->end()
+            ->scalarNode('store')->end()
+            ->scalarNode('index')->end()
+            ->end()
+        ;
+
+        return $node;
+    }
+    
+    /**
+     * Returns the array node used for "_ttl"
+     */
+    protected function getTtlNode()
+    {
+        $builder = new TreeBuilder();
+        $node = $builder->root('_ttl');
+
+        $node
+            ->children()
+            ->scalarNode('enabled')->defaultValue(true)->end()
+            ->scalarNode('default')->end()
+            ->scalarNode('store')->end()
+            ->scalarNode('index')->end()
+            ->end()
+        ;
+
+        return $node;
+    }    
 }
diff --git a/DependencyInjection/FOSElasticaExtension.php b/DependencyInjection/FOSElasticaExtension.php
index 53c91f1..92801ed 100644
--- a/DependencyInjection/FOSElasticaExtension.php
+++ b/DependencyInjection/FOSElasticaExtension.php
@@ -246,6 +246,12 @@ class FOSElasticaExtension extends Extension
             if (isset($type['_all'])) {
                 $this->indexConfigs[$indexName]['config']['mappings'][$name]['_all'] = $type['_all'];
             }
+            if (isset($type['_timestamp'])) {
+                $this->indexConfigs[$indexName]['config']['mappings'][$name]['_timestamp'] = $type['_timestamp'];
+            }
+            if (isset($type['_ttl'])) {
+                $this->indexConfigs[$indexName]['config']['mappings'][$name]['_ttl'] = $type['_ttl'];
+            }
             if (!empty($type['dynamic_templates'])) {
                 $this->indexConfigs[$indexName]['config']['mappings'][$name]['dynamic_templates'] = array();
                 foreach ($type['dynamic_templates'] as $templateName => $templateData) {
diff --git a/README.md b/README.md
index cb6e5f8..ade48ea 100644
--- a/README.md
+++ b/README.md
@@ -526,7 +526,7 @@ class UserRepository extends Repository
     public function findWithCustomQuery($searchText)
     {
         // build $query with Elastica objects
-        $this->find($query);
+        return $this->find($query);
     }
 }
 ```
diff --git a/Resources/config/config.xml b/Resources/config/config.xml
index 1fb2c1d..85cfbed 100644
--- a/Resources/config/config.xml
+++ b/Resources/config/config.xml
@@ -14,6 +14,10 @@
         <parameter key="fos_elastica.elastica_to_model_transformer.collection.class">FOS\ElasticaBundle\Transformer\ElasticaToModelTransformerCollection</parameter>
         <parameter key="fos_elastica.provider_registry.class">FOS\ElasticaBundle\Provider\ProviderRegistry</parameter>
         <parameter key="fos_elastica.property_accessor.class">Symfony\Component\PropertyAccess\PropertyAccessor</parameter>
+        <parameter key="fos_elastica.object_persister.class">FOS\ElasticaBundle\Persister\ObjectPersister</parameter>
+        <parameter key="fos_elastica.object_serializer_persister.class">FOS\ElasticaBundle\Persister\ObjectSerializerPersister</parameter>
+        <parameter key="fos_elastica.model_to_elastica_transformer.class">FOS\ElasticaBundle\Transformer\ModelToElasticaAutoTransformer</parameter>
+        <parameter key="fos_elastica.model_to_elastica_identifier_transformer.class">FOS\ElasticaBundle\Transformer\ModelToElasticaIdentifierTransformer</parameter>
     </parameters>
 
     <services>
@@ -37,7 +41,7 @@
             <argument /> <!-- index configs -->
         </service>
 
-        <service id="fos_elastica.object_persister" class="FOS\ElasticaBundle\Persister\ObjectPersister" abstract="true">
+        <service id="fos_elastica.object_persister" class="%fos_elastica.object_persister.class%" abstract="true">
             <argument /> <!-- type -->
             <argument /> <!-- model to elastica transformer -->
             <argument /> <!-- model -->
@@ -49,21 +53,21 @@
             <argument /> <!-- transformer -->
         </service>
 
-        <service id="fos_elastica.object_serializer_persister" class="FOS\ElasticaBundle\Persister\ObjectSerializerPersister" abstract="true">
+        <service id="fos_elastica.object_serializer_persister" class="%fos_elastica.object_serializer_persister.class%" abstract="true">
             <argument /> <!-- type -->
             <argument /> <!-- model to elastica transformer -->
             <argument /> <!-- model -->
             <argument /> <!-- serializer -->
         </service>
 
-        <service id="fos_elastica.model_to_elastica_transformer" class="FOS\ElasticaBundle\Transformer\ModelToElasticaAutoTransformer" public="false" abstract="true">
+        <service id="fos_elastica.model_to_elastica_transformer" class="%fos_elastica.model_to_elastica_transformer.class%" public="false" abstract="true">
             <argument /> <!-- options -->
             <call method="setPropertyAccessor">
                 <argument type="service" id="fos_elastica.property_accessor" />
             </call>
         </service>
 
-        <service id="fos_elastica.model_to_elastica_identifier_transformer" class="FOS\ElasticaBundle\Transformer\ModelToElasticaIdentifierTransformer" public="false" abstract="true">
+        <service id="fos_elastica.model_to_elastica_identifier_transformer" class="%fos_elastica.model_to_elastica_identifier_transformer.class%" public="false" abstract="true">
             <argument /> <!-- options -->
             <call method="setPropertyAccessor">
                 <argument type="service" id="fos_elastica.property_accessor" />