Woops, my question seems to be posted twice... My mistake ;-)
Anyway, since there are no replies at all, this doesn't matter, but it seems to confirm my statement concerning open source in general... nice products, no or poor documentation...
First of all thanks for your reply and I have to admit that the application server itself has very nice documentation. I posted my question and corresponding statement because I was looking (and googling) around for some particular information concerning building your own interceptors and invokers to gather some more knowledge about the bits and bytes of the JBoss microkernel. Are you aware of such information? Tutorials, sampe applications and stuff like that, allthough I could take a look at the JBoss source code off course ;-)