It's almost not possible to use the P900 with SE's own HCB-30 bluetooth carkit, let alone a nokia one! I wouldn't put money on it.
I've had an aboslute nightmare trying to get the P900 to work properly with my SE bluetooth carkit (HCB30) and contrary to what the salesmen say and the tech support muppets, they don't work well together. My old T610 worked brilliantly with it, but the P900... forget it... I gave up...
I've had too many near accidents trying to get the damn P900 to work with the HCB-30 carkit that I simply don't use it anymore when I'm driving...
SE claim the P900 & HCB-30 are fully compatible... I KNOW it isn't cos i have both and they don't.. I've got the latest updates etc etc...
For those of you thinking about buying a P900... take this free advice, DON'T BOTHER... you'll only be buying yourself into an EXPENSIVE headache. If you still want to buy one, look for second hand... the P900 second hand market is probably the biggest (and you'll get yourself a very good deal, cos previous owners would have just gotten pissed off with it that they would want to get rid of it for any price)... and second hand ones tend to be almost like brand new, because it doesn't take a long time till you start coming across all the bugs that people talk about.
The P900 as a piece of hardware is very nice... but the software is IMO still in Beta phase... if not Alpha!
P900 has probably broken all records for the phone with the MOST number of updates released for it! I'm sure all P900 owners will agree with me on this. There's an update released almost once a week!!! Now that says something about how thorough SE's engineers are when they roll out updates! So if you want to your time running backups / updates on your phone, this is the phone for you! But I'm sure people don't buy mobile phones to help the companies troubleshoot bugs...
I have written to SE many many many times reporting all sorts of bugs in the P900... my conclusion is that if there's a bug with an SE product, just live with it... cos they seem to have no idea of how to fix most of them (they actually go as far as denying some of those bugs exist! something that really ticked me off).
The mobile phone industry is going through a dark era... companies just want to rush the next product out to the market... the P900 is an excellent example.. that phone should have never been released in the first place... A year on, I still think its software is an early Beta (and I'm probably being nice to SE saying that).