Install PCI Drivers When Device Not Present

I have an embedded application where I can only run one PCI SCSI card which
is required for booting. While the system is up on card “A”, I want to
install the drivers for card “B” so that when I boot the next time, it will
automagically use card “B”. Is this possible? When I try to do it now, the
card “B” driver installs under Enum\Root instead of Enum\PCI.

How do I do it?