How To Add A Gauge To PMDG To 737NG

Hi to all of You!First at all, excuseme for my English. I try to write well.My problem is:I would like to add a gauge named radiocd4.gau to my panel of the great PMDG 737NG. As you see, I would like to hear some kind of music while I'm flying, specialy on those long flights.I'll been trying but the gauge doesn't see in the panel.I guess a good place to put it, there's will be in the radio stack.Ok, if anyone can help me, i'll be very thanks with him/her.EmilioUshuaiaTierra Del Fuego(Argentina)