I am having the same issue.
My N900 does not transmit voice over bluetooth, (I'm not sure if it trasmits my voice, but I cannot hear anything.) THis happens in my car and with my headset.

I noticed however that this did not happen right after I upgraded to PR1.2 I've had 1.2 for a while. It just happened the other day after I tried streaming music over bluetooth for the first time since installing PR1.2.

I had started a separate thread here, I don't know if there is any other useful information in there: http://talk.maemo.org/showthread.php...167#post723167