Saab Kenwood Navigation Video Input

Has anyone ever bothered with the video input on the back of the Kenwood SVT-M700 screen? Supposedly you should be able to display any video source on the touch screen. The KVT-M700 has its own button with which you can switch between the different sources (Navi or video input), which is missing from the SVT-M700. Maybe you have to press a combination of the keys (if you press the DISPLAY button long the screen goes off). also a schematic for the SVT-M700, I get really smart from it but not with regard to switching between the different sources. On the block diagram you can see that a switch is intended (see VIN left top) Has someone ever experimented there? I think it would be really crazy to connect an ipod video with cover flow there, not everyone would have… 🙂 Thank you for your help!