I have the Plantronics Discovery 640 headset and after starting the media player and a song I could hold the BT connect button for 2 seconds which transfered the song to the headset. Normally this button would start voice dial. It droped to speaker in-between every song but I could reconnect it when each song started. A Movie (Stewie Griffin Untold Story) worked great staying connected the entire time.

NOW...

I just tried it again and now it does not work.
Voice dial was broken where it would not open at all. that is why it allowed the audio to come through indefinitely until the media player audio stream stopped.
I pulled the battery to fix Voice dial and now media player will not come through the BT anymore.

Maybe someone can use this info to figure out a way to do it at will.
Maybe break the voice dial app on demad.

EMOrtal.

I ran into the same issue... Blue tooth audio worked great until I fixed my voice dialing feature.