yeah, that seems to be the case (that it's not possible) really sucks, but I guess I can live with it for now. it seems to show 2 cards in SLI if I use "Activate all displays" but not the 3rd. Only way to get all 3 it seems is surroundview, or Maximise 3d.
I did however run into another problem, my 2 monitors on the sides are 26" (30" in the middle) When I try to run an extended resolution for surround gaming, it says out of range on the monitors like they're not getting the signal. (the native resolution is 1920*1200, It won't let me get to 5760*1200, but will let me choose 5760*1080, but none of them work with the monitors. (I hope NVidia doesn't want them all to be the same monitors.)