I've been struggling with this very same thing for two months. I can connect the two via Bluetooth for Hands-free calling and phone book copying, but have never successfully got data services to work. I've scoured these and other forums for advice, tried a number of different manual settings, but nothing works. I finally broke down and asked TomTom support. They told me that at this time, the Bold is not compatible with the 730 for data services. Of course, when you look at the compatibility page, it shows that the Bold is compatible with the 730 for data services...whatever.
I'm putting this one on the back burner until RIM, AT&T, and/or TomTom get their s--t together, unless someone out there tells us how to get this combination to work.