I noticed the incompetence of the in-game AA; that said, I ventured, through one of my favorites of the "shader" based solutions.
Keep in mind that this requires you to disable any kind of AA in-game and through control panel in order to work properly.
Also, I made this preset an all-round enhancement, look at the comparison(will be adding some more screenshots)
preset and comparison screenshots:
http://sfx.thelazy.n...mes/preset/118/

The mod is avaiable as FULL package (with sweetFX binaries required to run it, and the preset tweaks) in The Witcher nexus:
http://witcher.nexusmods.com/mods/331

If you are struggling to get the antialiasing working with this game, try this, also applicable to those looking to make the game more beautiful, if you have any suggestions, feel free to comment.
This is a WIP, so, some brainstorming might just help the community have a better gaming experience.