Thank you nphelps( http://www.jboss.org/profile.jsp?user=1721 )!
A lot of kudos to you!!!
It was not that your idea helped me directly. But after I was already thinking I am a "java dumbass" (after 5years
of experience) I realized the problem was the f**cking windows ntfs filesystem which is case-insensitive.
The problem with that is: You got a jar - you look at it with a
zip-viewer (winzip or some other) - you see one folder
called "META-INF" in your archive. You think everything is
fine but nothing is fine because in reality there are two
archives: One "META-INF" and one "meta-inf". That's a real problem because even if you unpack it you only get one "META-INF" dir.
But for Java there are two dirs. That is against the J2EE spec and JBoss will not start the EJBDeployer. So my tip at the end: If you don't use a OS with a modern filesystem (i.E.: a *ix) - always use java-only tools when working with zips.