Sometimes I think too hard. I didn't *SUBMIT* the form on their link, I emailed them asking if it mattered if I knew my serial number (I don't -- the sticker got ripped off the back of the device as a side effect of an ill-advised experiment with some velcro).
If you just submit the form with "unknown" for the serial number, you get the links to the downloadable firmware. Everything installed fine, although the only odd thing was that I had to go download a device driver from a website in Taiwan, which makes the paranoid conspiracy theorist in me nervous.
I have the XGPS150 connected to HLT at 4.8 Hz now, and I'll report on my efforts to get it working when I get back on Monday.
Sorry to diss Dual on your forum, when the problem was entirely with the user (me
