So, I started looking around at the code of the executable that gets loaded in RAM once you run it, and found a bunch of strings that can be used to force options (think of them like command line options).
One of them is called "DX_CONFIG_DRIVER_AA_NOT_BROKEN" which makes the game think the driver's AA is not "broken" so you may have it enabled with no problems.
These strings/hacks can be put in the device.fix file (just open it with notepad).
Now you need to find your graphics card's id code, I got mine from here:
http://www.pcidatabase.com/search.php?device_search_str=nvidia&device_search=Search
(Just search for your own card).
So since my graphics card is a GTX 460 with an id code of "0x0E22" I needed to put these lines in the device.fix:
DEVICE Geforce_460 0E22
HACK DX_CONFIG_DRIVER_AA_NOT_BROKEN 1
like this:
http://i.imgur.com/cxEVa.jpg
Why don't you give it a try and see if it works for you as well?
PS It's very bad of them that they don't tell you this hack/string exists!!