SRAM Based PCI FPGA

Our company is currently developing software for a PCI card which has a fixed PCI bridge (with appropriate PCI configuration registers loaded from a ROM) and a soft loadable FPGA that does not have its PCI configuration registers loaded at boot time. There are some I/O pins on the PCI bridge which connect directly to the FPGA configuration load pins. During boot time, a device driver which loads for the PCI bridge will be responsible for loading the image into the soft loadable FPGA. Upon completion of that loading, the soft loadable FPGA (which contains a PCI core) will now have its PCI configuration registers appear on the PCI bus.

I am wondering if any one has implemented such a device. We need to support this type of adapter in Windows NT 4.0. This adapter is a Network card and thus an NDIS Miniport driver will be developed. Will the NDIS driver in Windows NT 4.0 be able to recognize this softloadable FPGA after it has been loaded? I am a bit concerned because the BIOS will not see that FPGA because it is essentially invisiable during BIOS loading. Given that the BIOS has the responsibility of allocating the actual base addresses of all the PCI devices, when this FPGA device appears, it will not be programmed with the appropriate base address.