Afaik amarok has no esd use flag and compiling xine-lib with the esd use flag should suffice. I even compiled amarok-1.4.2 final from source today without using any ebuild and reemerged xine-lib ad esd, still the same result. Seems that something else is borked on this system.
I will have to stick to slimserver for now when I want to stream music to my 770, fortunately that works well.
Anyway, thanks for trying to help.

Bye, Val.