Under regular conditions I almost always balk on trying to use drivers that were not meant to be be used on a certain Operating System, in this case, i might just recommend it. If the Sony site is plumb out of providing Windows XP support, and the "world wide web" has proven to be no help, than what I would recommend you to do is try installing Window Vista drivers for your XP O.S.! If Sony has Vista drivers that you can download, try and match the (bit) version, like if you have Windows XP (32bit) try using drivers for Windows Vista (32bit). If your Windows XP is a (64bit) than try a couple Windows Vista (64bit) drivers. The worst the web site is going to tell you, is that they detect that the drivers are incompatible for your O.S., and will not work.
Again I've never really liked using this course of action, almost never works, but on rare occasions I was able to slip a Vista driver or two past Windows XP nose and get away with it.
Good luck.......