title: Unable to generate route value_user_create
body: <p>I have a problem with my Symfony2-Project with SonataAdmin- and UserBundle.
  I installed and configured everything according to both Admin- and UserBundle-Documentations and tried to get it running, which seems fine for the start. So you can say that both Bundles come out-of-the-box.
  When I try to access the List of the users from the Admin-Dashboard (default Path <em>/admin/sonata/user/user/list</em>), then I get this:</p>
  
  <pre><code>An exception has been thrown during the rendering of a template
  ("Unable to generate a URL for the named route "value_user_create" as
  such route does not exist.") in
  "SonataAdminBundle:CRUD:list.html.twig".
  </code></pre>
  
  <p>As already described, neither did I change the default routing informations provided by Sonata, nor did I overwrite the Controller or anything.
  According to symfony console <code>router:debug</code> the route <code>admin_sonata_user_user_create</code>, amoungst other CRUD-routes, exists (pointing to <code>/admin/sonata/user/user/create</code>)</p>
  
  <p>So to me it seems like the value in route-name <code>value_user_create</code> does not get replaced by <code>admin_sonata_user</code>-prefix, but that's just a thought and I cannot prove it. Anyways I can't find any place to fix that problem, so every help and tip might be helpful here.</p>
  
  <p>Best Regards and thanks in advance</p>
  
  <p>edit:
  my sonata user service looks like this:</p>
  
  <pre><code>sonata_user:
      security_acl: false
      class:
          user:   Application\Sonata\UserBundle\Entity\User
          group:  Application\Sonata\UserBundle\Entity\Group
      admin:
          user:
              class:          Repertorium\AdminBundle\Entity\UserAdmin
              controller:     SonataAdminBundle:CRUD
              translation:    SonataUserBundle
          group:
              class:          Sonata\UserBundle\Admin\Entity\GroupAdmin
              controller:     SonataAdminBundle:CRUD
              translation:    SonataUserBundle
  </code></pre>
  
  <p>After first comment here I created my own UserAdmin-Class which is derived from the default Sonata\UserBundle\Admin\Entity\UserAdmin-Class, except that it sets the baseRouteName to null as mentioned.
  As config says I'm using the default AdminBundle-CRUD-Controller. No override in that case or anything.
  Cleared cache, tried again - same error message. Also tried to set it to a Literal such as "user_admin", but same none-effect.
  Weird thing is, that all other routes seem to work fine; I can open the create user-page, as well as create group and list group-pages.</p>