2002 Maserati Spyder USB, MP3, Bluetooth Adapter

I have a Maserati 2002 Spyder with the "Maserati Info Center." This is a unit with a video screen that has integrated to it all of the electronic workings of the car. The computer that calculates MPG, the CD player and changer, the radio, the GPS (if I had one)the phone if it were in Europe are all handled through this unit. It is mostly (but not all) Blaupunkt equipment but the Blaupunkt techs say their adapter will not work. I'd like to introduce a USB port into my system so that I can play mp3 audio. If possible I'd like to use the video screen to display photos. The closest I've come is the Dension company whose web site says they have what I want but after talking to a tech there who said their stuff didn't work in a Maserati.