Android: activating screen disconnects phone call

When you are calling the customer service of a Belgian phone company you can go into the waiting queue for a looooooong time. So i put the speaker on and have the waiting music loop while I continue working. When they finally pick up the phone, half an hour later, the phone screen has gone in sleep mode. So... I press the power button to switch the screen on (and switch the speaker off), which ... ends the call I've been waiting for so long. Aaaaargh...

How to disable call disconnection when you activate your screen with the power button on Android (4.0)?
Go to Settings > "Accessibility" and uncheck "Power button ends calls".
Unfortunatly you will also loose the intuitive facility to end a phone call using the power button.
 
Pushing the button when the screen is off should wake up the screen, pushing the button when the screen is on and a call is ongoing should end the call.
Hope Google guys correct his in the future. Please?