Home Phoneline Networking query.

I recently installed Diamond 10MBps PCI Home Phoneline Network cards in 2 different PCs. I am able to communicate and transfer data just fine. I am using one in a W2K PC as a server for modem so it can be used for internet connection sharing. My problem is that when I try to set up the Win98 PC to connect to the server for dial-up, the set up program doesn't recognize the Diamond HPA card as a network adapter and won't install the program. Any ideas for a fix.