Sharing USB Multi-function Devices

I have a Lexmark X73 multi-function printer/scanner/copier with a single USB port on the back, and I'm trying to share it between two PC's. Now I know I could share the printer function out over my network, but not the scanner/copier functions. So I looked around for USB printer switchboxes -(like the old parallel switchboxes) and there aren't many available. I ended up buying an ATEN unit from:
http://harbourtownsales.site.yahoo [...] witch.html

One PC is running Win98, and one is running Win2000Pro. The Win98 PC works fine with the Lexmark printer with or without the USB switch in the middle. And the Win2000 PC works fine when directly cabled to the printer - but the Win2000 PC does NOT work when the USB Switch is introduced (I've swapped USB cables and tried all 4 ports on the switch). It does get a partial signal though (evidenced by a page feed working, but print jobs failing, also using different cables yields different results: certain USB cables cause the PC to detect a new unknown device).

Has anyone had any experience sharing USB devices with a switch in Win2000? I can't figure out how the Win2000 PC even knows the switchbox is in the middle - it should be a straight pass-thru.

Helpful suggestions are welcomed.

Mike...