what version of the client are you using and what is the OS? we did have an issue where some card scanners didn't work with view that were fixed in the new clients. but it might not be the same problem you have.
please try with the most recent client version as there have been some fixes in that for USB. Also, the 5.3 guest may help (I don't know what the problem is that you are having, but the 5.3 agent has an updated driver). Note that if your problem was purely the WAN latency then I don't think going to 5.3 would make any difference there.
but it does sound like there is something stopping the scanner working in a local environment so do try the newer client first please.
cheers
peterB