I did not find any info about this in that forum so I add it here. If any moderator find a better place for it, please do move this post.
I am running Gentoo 2.6.34-gentoo-r12 with ATI Catalyst 10.10 (not taken from an e-build).
After several tests, I realized that I must not set the Catalyst AI
to "Advanced" (CCC -> 3D -> More Settings). I can have it active but only on "Standard". Otherwise, I will get strange graphics glitches in game, in particular when opening the fitting tool (colors go crazy and it becomes unplayable).