Which pad do you have. The pad 2 has bt. 2.1 specs, and is designed to work with speakers, headphones and keyboards. The pad 3 has bt 4.0. I have not heard a report one way or the other on what devices it now works with, but a starting place for you would be to see what bt profile the Tom Tom uses. If the pad is not seeing it, I think that is a bad sign.
The 3/4 g pad has built in gps, while the wifi only does not. If you have a g pad, you really don't need the external device.
The thread a Brody pointed to is one on many threads on external gps devices. there are not a lot of success stories of folks suing them.
Lastly, take a trip over to the Tom Tom website, and look in their support section. I would bet that others have asked the same question, and the answer may be sitting there for you.