Hey Juiceme,
Sorry for late reply but I'm very interested to hack this device as it is no use for me rigth now.
I have opened it with a simple knife and it probably killed the sealing but it is good enough to close it back.
Here are some pictures:




Careful with the back cylinder shape metal piece (magnet?), two wires are connecting it directly to the motherboard.





Unfortunately I don't have a oscilloscope to research some more
....

After some research on internet I found a pretty awesome project:
http://randomcontent.wolfnexus.net/R...e/arduino-hrm/

He is using a RMCM01 chip that reception and filters the signal (5Khz) and outputs a 1 ms pulse at 3V for every heartbeat detected.

Do you think we could simply connect this chip (RMCM01) to a bluetooth emitter and voila ?