Hey David, you changed your screen name. Did you become a year older???
I just found out (by accident) yesterday that my C class doesn't buzz at all. It only beeps when I drive with the E-brake on and when I get out with the key in my hands and the lights still on.
If your light system is connected to the beep and the buzz is only used for the opened doors whilst the keys are still in: disconnect the plug to that buzzer! Who needs it? (the european models do not have that buzz at all)
with a minor 600+k