Polycom IP500 headset mode will not stick

Is there a way to force headset mode ALL the time? I clicked the checkbox in the gui for headset memory mode. Then I edited the .cfg file and changed it from a 0 to a 1. Nothing I do will make it stay in headset mode.

Reason is I am trying to use a wireless headset with the handset lift arm. When I press a button on my wireless headset, a little motor lifts the handset from the cradle to answer the call. That’s fine but the phone imediately reverts to HANDset mode. I have to run back to the phone and press the HEADset button so I can talk.

Any suggestions???