I AM following the manual, so I don't see what it is that I am not doing correctly. Here is what I have done as far as startup:

Brake select switch to emergency, anti-skid off, temp datum controls to auto, condition levers/throttles set to ground stop and ground auto. I starting up using ground power so I select the captain sim menu and select ground power. I see the green banner indicating ground power is connected. I turn on the external AC and DC power followed by turning the radio on. The next several steps I follow are turning on the switches on the GTC panel. I set the inverters to match the yellow stripe on the panel. After following a couple more steps, the engines are ready to be turned on. AFter turning on all four engines, I switch to the external view and verify that all four engines are running. Once engines are running, I turn off the GTC and the external ac power followed by turning off the external ac power.

The next step in the manual I am following indicates I can tune to the clearance delivery and request an IFR flight. THIS DOES NOT WORK. The radio is already tuned to the right frequency, but the default ATC does NOT respond to any key pressed on the keyboard.

I'm going step by step following a manual which provides detailed instructions on startup. So, with all the engines started and ground power disconnected and external power turned off, what could I possibly be missing?