2x 8400gs pcie and 1 fx5200 pci QE/CI.
From a clean install i installed nvdarwin installer 1.2.4mpkg and rebooted .Then i ran easy efi studio and added 1x8400gs and restarted and finally i used easy install nvinject to add the nvinject 0.2.0 dual cards kext.Rebooted and was amazed that i have 3 cards all with full support.
I have been searching for days on the net to try and get just 1 card working properly.
If you wish to see the kext or plist let me know. Hope this help.