Is it possible the printer is broken?
I can't test XP since I haven't seen it for a few years and have no access to it, but since MS doesn't in any way update it, and all these options have worked since day one it seems like you may have a broken printer, not an issue with Windows XP.
The driver should be on the disk that came with it. But Xerox and every other company dropped all support for XP at the same time Microsoft did, so nothing will be found on Xerox.com, you already tried the XML pack and .net and they failed to, so not only are you using XP, but your installation of it is bad.
So if you can't manage to install this driver (oldest linkable Xerox driver still hosted) then you are out of options.
Won't recognize the supplied drivers. Tech support phone call resulted in a blunt "we dont support XP" response...I bought this specifically because I was told it did support XP. Anyone succesfully run this on xp?