How do I change the light bulb in my Whirlpool GMC275PD microwave?

The Whirlpool GMC275PD is a combo electric oven/microwave. Last February the microwave bulb burned out. It just burned out again!
Because Whirlpool designed this like it was for the military it requires a service call and removing the unit from the wall to access the bulb. In addition the Whirlpool replacement bulb is priced around $55.
The first replacement cost me $182! I would prefer not to have to pay that again. Can you help with how to replace the bulb myself? It looks like a Sylvania 58652 at about $6 might be a substitute for the factory bulb.