PCI modem – MS-DOS

I have a Diamond Multimedia SUP2260 PCI 56K supravoice MAX modem. I am able to have it work with Windows 98. When I try to use it with MS-DOS applications, Dos will not recognize it at all. I tried changing the IRQ to 3 or 4 and also I tried enablling MS-DOS support on the Dos support tab. Both of those things have failed. Is there some way I can get this modem to work with MS-DOS? and please dont tell me to buy an ISA modem. I have moved this modem to another slot and the IRQ changed from 11 to 10 and I only have 3 PCI slots.