i have nvidia cards, the gts250 two of them in sli, on a crossfire only system which is nice. but there is no difference between crossfire and sli in hardware. its only the drivers that forbid sli on crossfore and crossfire on sli. a simple sli patch makes it work and all that patch does is tell nvidia drivers that the motherboard is a sli motherboard
and so far all my other games have worked fine in sli.
i'll try and change the config.ini then a bit
10 minutes later...
AWESOME! it worked, changing the cfg.renderdevice to 2, thanks very much! now the developers should perhaps wonder why this was the problem and please try and correct this