class frontendConfiguration extends sfApplicationConfiguration
{
  PRotected $backendRouting = null;

  public function generateBackendUrl($name,$parameters = array(),$absolute = false)
  {
    return sfconfig::get('app_site_url').$this->getBackendRouting()->generate($name,$parameters,$absolute);
  }

  public function getBackendRouting()
  {
    if (!$this->backendRouting )
    {
      $this->backendRouting = new sfPatternRouting(new sfEventDispatcher());

      $config = new sfRoutingConfigHandler();
      $routes = $config->evaluate(array(sfConfig::get('sf_apps_dir').'/backend/config/routing.yml'));

      $this->backendRouting->setRoutes($routes);
    }

    return $this->backendRouting;
  }
}

像这样用它：

$sf_context->getConfiguration()->generateBackendUrl('my_custom_route',array('id' => 1),true)

更多信息：http://symfony.com/blog/cross-application-links