I gave up on modifying the Dot keyboard and bought a Logitech Internet Navigator "multimedia" USB keyboard ($19) and Logitech optical USB mouse ($10) from PCIMicro here in California.
Both work great, but I had a little trouble getting the OS (Win98SE) to install their drivers. I plugged both in, and the Install New Hardware dialog froze since neither keyboard nor mouse was working at the time (though the keyboard had worked fine to get into the BIOS).
It turned out that Windows was installing the mouse first, which I discovered by plugging in the Dot keyboard and the Logitech mouse. The Dot keyboard worked fine to navigate through the mouse installation, then I replaced it with the Logitech keyboard, which installed fine since I could now use the mouse to wade through the installation dialogs.