How disable route call to bluetooth headset if received via device?

[Murz]

Before Android I use Windows Mobile phone and it have the feature: if bluetooth headset is connected and I answer call via device, call routes to device speakers, not in headset. But if I answer call via bluetooth headset, it route call voice to headset.

But Android on my device (HTC Desire, Cyanogenmod 7.0) always route call to bluetooth headset. Also, when I manually try route call back to device from headset ("private call" option that disconnect current headset connection) it routes to device, and after some seconds - back to headset.

How I can disable automatic routing all calls to bluetooth headset?

 

[pool_shark]

I don't recall my Omnia having that feature.
I'm not sure what options are available to you other than either turning off the headset, or turning off Bluetooth.