Just checking with all you that know these phones better than I do.
I have a BOLD 9000 and a Motorola H700 Bluetooth Headset (NOT A2DP).
I started to play some music on speaker and forgot I had my bluetooth on while driving. The music streamed through the earpiece---I was shocked because I didn't think that was possible. It lasted for about 30 minutes until I got a call and then I couldn't get it to happen again.
You should be able to do it again - I've gotten an H500 to play music. After you pair it up, start the music application and play a song. If it plays through the loud speaker or handset, push the menu button and see if there's an 'Activate Bluetooth' or 'Activate Headset' option.