Set Primary Graphics Card in BIOS

[ressiehcs]

Mainboard: http://www.msi.com/index.php?func=proddesc&maincat_no=1&cat2_no=170&prod_no=1485
AMI Bios

I'm trying to use 2 graphics cards in this mainboard: ATI 5970 in PCI-E Slot 1 and Nvidia GTX 280 in Slot 2. I would like the ATI card to be the primary graphics card but for some reason the bios always sets the Nvidia card to be the primary graphics adapter.
There is an option in the bios called "Primary Graphic's Adapter" but I can only choose between "PCI" and "PCI-E".

Is there a way to force the bios to always use the graphics card in slot 1 as primary graphics adapter? Other mainboards with AMI bios even allow you to choose between "PCI-E Slot 1 " and "PCI-E Slot 2", maybe this could be added to the bios?

[edwin]

What happens if you physically swap the cards, does it still behave the same?