If you're still having problem with the Tiger usb device plugin hack, try mounting the Sony GPS unit to a NAS drive that has USB input.
I found couple of sites that basically says to mount the GPS unit to any NAS device with USB input, and hopefully the device recognize the GPS unit as a USB drive.
Then just connect to that drive over network.
http://int.cocolog-nifty.com/osakanarrow/2006/12/gpscs1k_7012.html
it's in Japanese, but pretty self explanatory with the pics...
I have yet to try this method... I don't know if Apple brand Airport unit will recognize it but who knows... Since I don't have any base station, I can't say...
the blogger seems to be using a NAS device which runs linux kernel...