Retrofiting nav system in mercedes w211?

Hello — I want to upgrade my W211 Mercedes from the Audio 20 (standard radio) to an NTG1 satellite-navigation system. I’ve read forum posts from people who have completed this upgrade, but I can’t find a wiring diagram or reliable technical information. Could you help?

My vehicle currently has the Audio 20 with the 6-CD changer. The Audio 20 uses a quadlock connector with two MOST fiber-optic cables. The NTG1 uses different connectors: one connector with two MOST fiber-optic cables and four pins, and another connector with three small pins. Any assistance would be appreciated.