Use a bluetooth headset as a extended microphone for a camcorder using android phone

I'm trying to film a video with a camcorder. However, the camcorder isn't support bluetooth microphone. Fortunately, I think I found a way to do it, but I can not find good app to do it. My plan is, use phone as a bluetooth receiver, and connect the audio port of the phone to the camcorder via cable. I need: an app that make the bluetooth headset as a default microphone of the system. an app that make the sound from the bluetooth mic able to flow to the audio port.

I know about an app called "megaphone" in Apple store that makes sound from the phone's mic flows through to the phone's audio port. But I can not use the bluetooth headset for it.

Any suggestion please?