1. Make sure your Bluetooth headset is active – make a test call and then hang-up.
2. Start playing an audio media file.
3. Switch from speaker phone to internal handset speaker (BB button, “Activate Handset Speaker”).
4. Call your BB from another phone.
5. Answer the call – it should automatically pause the audio playback and pickup the call on your Bluetooth headset. Make sure that you can hear the phone conversation on the BT headset by inanely asking yourself “Can you hear me? Can you hear me now?”
6. Now for the proof – hang up the phone call.
7. For just a few seconds you’ll hear your media file restart playing on your Bluetooth headset – then the Pearl software will catch up – oops – that’s a media file – I’m not allowed to send that to the BT headset and redirects it to the internal handset speaker.

The whole point is that RIM has apparently made a decision not to allow the media player to use BT headsets – while the hardware does support it. I have opened a ticket with RIM requesting that they fix this (as a bug report) – so I can use my BT headset to listen to media files – and it regularly gets closed citing “no response from customer” and then I call back and re-open it.

i think you may need to check that!