It apparently does support it. I was able to see text messages on my BMW 550's iDrive screen earlier. During pairing, I got a MAP Access request.
However there appears to be some kind of bug. When you go to Advanced Options in Bluetooth Settings, the only thing you see if FTP Server. However briefly other options flash and then disappear. Once earlier the options 'stuck' but if you'd check them they wouldn't save.
Hopefully the forthcoming OTA fixes this. I was really hoping this phone would show contact pictures in iDrive. The Sensation supports this. I suspect something in Bluetooth needs to be enabled that is not. (I borrowed a Lumia 900 with WP7 and it did this -- quite cool.)
Can anybody else test to see if the Advanced Options menu does the same thing?