SiS530 chipset onboard wth two monitors?

I have an AMDK-6 from pcchips model m598 and it has the SiS530 chipset on board with the number 5595 on it, can anyone out there tell me if there is a way to use the onboard 8M agp video adapter as the primary video card and then install second video adapter in pci slot to use as second monitor. I get the computer to recognize both but device manager says the primary video adapter driver does not support dual monitors. Does anybody have a fix to help me out it would be greatly appreciated.
Thanks, J.R. Cole