Can't play with Crossfire

I have 2 AMD 270x on Crossfire and the game shows big black artifacts continuously with Crossfire enabled. If I disable Crossfire, the game runs fine.

When I played Warband or cRPG, without disabling Crossfire, I never got artifacts or any issues. The game just always ran with only 1 GPU.

So my guess is that Caribbean! does support Crossfire - after 5 minutes playing, both GPU's showed 45+ ºC with RealTemp (if it used just 1 GPU, one of them would stay around 30ºC) - but it's unplayable due to the artifacts. After a couple of minutes playing, it got to the point where half the screen was black and I got a lot of script errors and missing text in conversations.

Please address this issue, because, even though the game runs perfectly fine with just 1 GPU, it would be better to make use of Crossfire, and we wouldn't have to be disabling and enabling it every time we play this game or another.