diff --git a/DependencyInjection/PropelExtension.php b/DependencyInjection/PropelExtension.php
index f277742..e922f11 100644
--- a/DependencyInjection/PropelExtension.php
+++ b/DependencyInjection/PropelExtension.php
@@ -106,6 +106,7 @@ class PropelExtension extends Extension
         $c = array();
         foreach ($config['connections'] as $name => $conf) {
             $c['datasources'][$name]['adapter'] = $conf['driver'];
+            $c['datasources'][$name]['slaves']['connection'] = $conf['slaves'];
 
             foreach (array('dsn', 'user', 'password', 'classname', 'options', 'attributes', 'settings') as $att) {
                 if (isset($conf[$att])) {