Thanks for your reply Ron, which I read just now (Didn't check this thread anymore).
I secured my described system with spring security 2.0 (formerly acegi), which - after some time and hard learning - does the job pretty well for me.
But I will have a look at your suggestion pretty soon...
[Message sent by forum member 'callisto79' (callisto79)]
http://forums.java.net/jive/thread.jspa?messageID=272848