Haven't tried the FE's panel so far, only looked on the Captain's side. I also thought that the FSX key command will override any VC setting.
But thanks for that input, audiohavoc, I will try again and also revert back to the faulty gauge file to see if the missing Markers are bound to my small modification.
Otherwise, I will live with the lights only and enjoy the rest of the cockpit sounds on the first load.

Mark, seems like you are investigating now, huh?
By the way, are you getting the Marker sounds on your system?

[edit]Thanks, audiohavoc, I finally found the marker sounds. You are right, the FE panel toggles them. Loud and clear now.  :)[/edit]