How do you enable forced AA?

I enabled 16xQ in the game and get 43-48 fps with a GTX295, but I'm using "Enhance the application setting" instead of "Override application setting".

16X on anistropic, supersample, textLOD-clamp, textfilt-highqual,
trilinearopt-off, triple-off, max-pre-rend=1, vert-sync=off