diff --git a/lib/neutron_plugins/ml2 b/lib/neutron_plugins/ml2
index b5b1873..ab4e347 100644
--- a/lib/neutron_plugins/ml2
+++ b/lib/neutron_plugins/ml2
@@ -54,11 +54,7 @@
     Q_PLUGIN_CLASS="neutron.plugins.ml2.plugin.Ml2Plugin"
     # The ML2 plugin delegates L3 routing/NAT functionality to
     # the L3 service plugin which must therefore be specified.
-    if [[ $Q_SERVICE_PLUGIN_CLASSES == '' ]]; then
-        Q_SERVICE_PLUGIN_CLASSES=$ML2_L3_PLUGIN
-    else
-        Q_SERVICE_PLUGIN_CLASSES="$Q_SERVICE_PLUGIN_CLASSES,$ML2_L3_PLUGIN"
-    fi
+    _neutron_service_plugin_class_add $ML2_L3_PLUGIN
 }
 
 function neutron_plugin_configure_service() {