Also, the small wierdeness in the ears (still remained, though less now) can be simply edited out in photoshop. Just use the smudge tool to cover up the inconsistencies with a blurred-down tone of the surroundings…
I’m sorry but i don’t have much time at the moment. I hope i can post new results in a few days.
Thanks a lot for your help, i really appreciated it!
I’m back 
Ok, after a long break i continued my work in the new year 2008.
After testing a few things in the last weeks, i decided to completely retopo my mesh and with the new topology my uv-problem was gone. 
(but i always still don’t know what the reason for my strange normal-maps was…)
Now i was able to create my normal-map with ZMapper and my displacement-map with multi-displacement-3.
result:
Thanks again Megamorph for your help! I learned a lot!
I will show future results now in this thread:
http://www.zbrushcentral.com/zbc/showthread.php?t=50770