[fw-mvc] Enforcing ACL with Zend_Navigation?

I'm using ZF 1.8 and the new Zend_Application component. I've set up my navigation configuration in application.ini and created an ACL in models/Acl.php. I've tied the two together using the navigation view helper:

// In config

resources.navigation.pages.news.label = "News"

resources.navigation.pages.news.resource = "news"

resources.navigation.pages.news.privilege = "list"

resources.navigation.pages.news.controller= "news"

resources.navigation.pages.news.action= "index"

resources.navigation.pages.news.route = "default"

resources.navigation.pages.news.label = "Write News"

resources.navigation.pages.news.resource = "news"

resources.navigation.pages.news.privilege = "create"

resources.navigation.pages.news.controller= "news"

resources.navigation.pages.news.action= "write"

resources.navigation.pages.news.route = "default"

// In bootstrap

$acl = new Default_Model_Acl();

$view = $this->getResource('view');

$view->navigation()->setDefaultAcl($acl);

$view->navigation()->setDefaultRole('guest');

Everything is working fine so far. Only "allowed" pages appear in the navigation menus.

My question is, what would be a good way to enforce this in case the user accesses forbidden pages manually? For example, if guests are denied to create news, how can I keep them from accessing the page at /news/write?

In my application, the controller name is not necessarily the same as the ACL resource, and the action name is not necessarily the same as the ACL privilege. However, I would like to be able to query the ACL before the action is dispatched (perhaps from within a plugin) so I can forward the user to a forbidden page when not allowed.

Is there any easy way to ask Zend_Navigation "is the current page allowed by the ACL?"

Thanks!

-Hector