Maybe you forgot that i have written lots of scripts to test various variants of xbmc branches, also the ones that support xvba:
Needs this in case you dont have got Kanotix:
You can install depends as root and as user it will dl and compile it. If you update wipe out ~/dist before.
I tested xvba since the very beginning, but today i could playback my l5.1 testfile. Well i dont use fglrx all the day, i did so with an ati 9700/9800 pro but not later.