Ok ... after another googling Session one of the pages unavailable fpr the last days was online again and I found a solution to my problem. Instead of adding a "Class-Path" Element to the MANIFEST.MF File I have to add a module to my application.xml file:
Just thought I should post my solution so it might help somebody else.
Haha ... what an intelligent system to stip off the xml-tags ...
well I'll just replace "<" with "[" and ">" with "]" :)
Eat this! ;)
<module> <java>lib/jakarta-oro-2.0.6.jar</java> </module>