2000 Jetta cd changer install

I just installed a factory cd changer in my 2000 Jetta, but the head unit still reads "no changer". The changers plug has 10 terminals, and the plug in the car has 9. Can anybody tell me if this is the problem, or does it have to go to a dealer to get the head unit reprogrammed.

I believe you ned to use a VW scanner or simulator like VAG-COM to recode the radio to look for the changer. It's a fairly easy operation.

I thought that's what I needed to do, but what about the different number of terminals on the plugs?