TastyPie - Override_urls ignores Authentication and Authorization

I have the following resource:

class MyUserResource(resources.MongoEngineResource):

    class Meta:
        ...
        authentication = MyKeyAuthentication()
        authorization = ApiKeyAuthorization()

    def override_urls(self):
        return [...] 

All API calls which are standard-tastypie are routed through the authentification and authorization. But all customized functions/urls (which are in my override_urls) simply ignore the auth/auth functions...

Any ideas why?

Edit:

Maybe the problem is that the dispatcher isn't called. The question remains why that is... and how I can change this behavior!