How are you getting on Zepp? I have an interest in this issue 'cos I have a similar problem.
My Dell is basically a PCI based PC with one floppy drive. There is one (E)ISA slot. I run Windows 2000 in which the "Plug 'n Play" is brilliant - until you come to the ISA interface.
I want to fit a "Legacy" dual mode floppy (5¼ and 3½) that worked fine in an old 486 with the ribbon cable plugged into a standard ISA I/O card.
The BIOS only supports a single FD and the Dell Floppy Drive Controller is buit-in to the motherboard. The I/O card is therefore essential but the Dell won't "see" it. Just as in your problem the system won't "see" the Lava card. I don't have a driver for this but I think you said that you did for yours.
Dell are at last trying to help, but without much luck. I've e-mailed Canon who made the Dual Floppy.
In the meantime I wondered if you'd had success and if so how?