I'm speculating here. The MSI hack is as if you are paired with two devices, the MSI stack and the Microsoft stack (though I know this is all through one BT radio on the 6700). So, if your headset supports pairing with multiple devices, I think you will be able to take calls. I'm guessing if it doesn't work with the dongle, it won't work with this app either.

It works with my headset. The phone rings audibly through the 6700's speakers and then my Sonorix headset beeps, I hit the phone button on the headset, take the call, hang-up on the headset and the music returns.

S.