Erm, first of all, you are aware the Touch doesnt have GPS built in, and as far as I am aware, Bluetooth GPS isnt supported yet?? <or is it?>
The only method that I know of, but dont think the device is out yet is the i360GPS....
But TomTom will run just fine on v3.0 of the firmware, it also runs fine on 3.1.2.
I have the Touch 2g model, and its worked fine on the above firmwares. When I say run, it loads and works, but of course NO gps. I just installed it, as I am support many friends on iPhones. So I test SatNavs for people...
To answer your question. The Tomtom cradle comes with an inbuilt gps chip & I don't want to pay £99.99 if it won't work with my current touch firmware.