I dont have a ATI-Card at the moment, but have had in the past!
If i remember correctly the ATI-Supersampling is called "Adaptive Anti-Aliasing"...
You can activate it in the Catalyst control center. Make shure you disable the "High dynamic range" setting
in SABOW, as this is not compatible with extern AA-settings. Maybe this is different on ATI-Cards...
Site with infos: http://www.tweakguides.com/ATICAT_7.html
Just try it out and report your findings.
Ingame AA doesnt do the same thing! The image quality is far better with activated SSAA, accept it or not! Its simply in the physics of the AA-Method.
You dont even tried it but keep posting wrong facts! Instead of shooting against methods that let this outstanding game
look even better...you could just build your knowledge up and give proper advises...
And of course: there isnt a bug with negative MIP-bias, its only a method of letting distant textures look sharper. Even without this Supersampling AA does look far better than ingame AA! Just read the link i posted...
I hope you dont feel attacked by me, i just want to correct this wrong oppinion.