Well, I can confirm that xerox 3117 works fine through wl500gP using Oleg's fw raw 9100-port printing (default way of printing in Oleg's fws).

Theoretically, every USB printer should work with the RAW option
Unfortunately, it is not completely true statement, as some (luckily minority) of USB printers require to have some firmware to be uploaded before printing. Some HPs (probably, 1018 and 1020) require it.

P.S. actually xerox 3117 is manufactured by samsung (its equivivalent is samsung 1610 or 1615).