As of right now, the Droid doesn't support much functionality for the BT HFL (Hands-Free-Link) Profile.
Currently, about the only portion of the HFL Profile that *is* supported is phone audio for a previously initiated call.
Initiating a call (or other phone commands) via the headset, and routing non-call phone audio to the headset are not supported at this time.
It is not clear at this point if Android phones will ever support these (and other) HFL functions. Some of the claims I have read for why the HFL functionality is limited is due to the Universal Voice Search functionality, which routes your audible commands up to Google for analysis instead of analyzing the audio on the phone itself. Whether this is the real reason or not, I can't say - I don't know enough of the technology being used.
FWIW, these issues are currently at the top of the Android Bug Tracker list (under
Issue #1181). If you want this issue (or any others) to be raised higher in the A.B.T., just click on the star on the left side, and you will be added as a subscriber to that issue (and the "Star Count" will be incremented for that issue). You don't need to add a useless "Me, too!" posting in the issue thread to have your vote counted.
Cheers!
AzJazz