I'd consider changing dealers as they are obviously pretty clueless (or they're covering up their mistake). I have both Nav and the BT/Assist module...factory ordered and built in March '05...and they work flawlessly together. Very happy with the results...especially the performance with my Motorola V635 bluetooth cellphone. I'm in Calgary so it is certainly the case in Canada.

If you want BT now it is possible to retrofit, but it will probably cost considerably more than if factory installed.