Even though they claim that you can't use it, I would try anyway. As long as you have bluetooth that can be enabled on your phone, who knows...you might get lucky. Just dont get confused when you have to "pair" your phone with the car.

Worst case is that you cant use your p.900 and you can buy a cheap crappy bluetooth phone on ebay and switch out sim cards when you take long trips...thats kind of a pain but if you want to keep your sony theres not much else you can do. It may be possible for the cell retailer you have to program you a new duplicate sim card. I dont know if they will or not.