Well if it is not showing on the KVM, chances are it is just not compatible, but it because of lack of power or just an unsupported chipset.
It is kind of hit and miss with these things.
shame they do not sell these any more
http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpNo=1187801
While they do not switch video, many screens have more than one input now and you can share upto 7 devices and switch each one.
They still have a 4 port version on sale here(specs say usb 1.1 and 1.0, strange as the one I had was 2.0 for sure), but I have never bought from them(got the exact same thing at walmart like 7-10 years ago). It does introduce a small bit of report/sec lag into some mice while the 8 port one does not seem...