If you are talking about using the Sony CD changer with the Monsoon system, I don't know of a way it will work. Each auto manufacturer works with specific stereo companies to develop their OEM systems. Panasonic has been the source for VW for some time now and as such, Panasonic changers usually connect right up to OEM headunits. Someone may make an adapter but I tried searching a bunch of places on the internet and couldn't find anything to help you. Sorry.
A forum community dedicated to all Volkswagen owners and enthusiasts. Come join the discussion about performance, builds, modifications, classifieds, troubleshooting, maintenance, new releases, and more!