CakePHP ACL - On the fly permission management?

Greetings!

im pretty new to cakePHP and just starting to use the ACL feature.
From the outside it looks quite ok, but when i started using it.. well its not that ok anymore :)

Im working on an application with an administration backend in which i need to be able to change group permissions on the fly. I tortured google for quite a while now and i couldnt find any good example on how to implement that. I found tons of posts about the command line tool, but i'd like not to use that out of my application.

Does anyone know a way to implement this or a decent tutorial/howto which addresses that?