dunno about the SCART idea, but in the How To on adding a reverse cam, and then other threads about adding video / games consoles, they have used the circuit which makes the Civ think it's in reverse gear.
a bit of clever dohickery there should do the job I think!
but I wouldn't even begin to think about doing it myself - MUCH better left to those who know what they are doing!
Such as the people who did the above mods, just to clarify
i want to attemt to install the above mods but i supose if there is no way of getting around the sound then really you could wire it up to a fm transmiter. i'll have ago when i get my car "getting it tomoz "