Don't require the dummy routing file anymore for automatic route generation. Instead provide a "type" in the routing file to trigger automatic route generation. An example routing file might look like this now:

admin:
    resource: @SonataBaseApplicationBundle/Resources/config/routing/sonata_base_application.xml
    prefix: /admin

_sonata_base_appliation:
    resource: .
    type: sonata_base_application

The _sonata_base_application route will trigger the AdminPoolLoader routing.

Resources/config/routing/sonata_base_application.admin

@@ -1 +0,0 @@
-dummy file to load the Sonata\BaseApplicationBundle\Route\AdminPoolLoader

Route/AdminPoolLoader.php

@@ -33,7 +33,7 @@ class AdminPoolLoader extends FileLoader
 
     function supports($resource, $type = null)
     {
-        if (substr($resource, -29) == 'sonata_base_application.admin') {
+        if ($type == 'sonata_base_application') {
             return true;
         }
 
@@ -42,7 +42,6 @@ class AdminPoolLoader extends FileLoader
 
     function load($resource, $type = null)
     {
-
         $collection = new RouteCollection;
         foreach ($this->pool->getInstances() as $admin) {
             foreach ($admin->getUrls() as $action => $configuration) {