Rear view mirror dashcam with rear and front camera

[mapuche6]

Hi guys,

Five months ago I had a severe scratch in my car (Audi RS 3), well in fact someone scratched it with not apparently reason, when it was parked in a Tesco car parking in Camberley. Since then I was motivated to fix in it a dash cam with car parking mode. After considering several options, at the end I decided on a rear view mirror dash cam with a front and rear camera which could be be used as a reverse camera too. As I was much more comfortable having fitted a device with these two cameras (rear camera for parking reasons and it kept clear my wind screen. The store where I bought it, www.figtail.co.uk, was nice: below of average price, top quality products and excellent customer support.

My point now is that rear camera is working as a reversing camera (connected to the reversing light cable), so when I put reverse gear, on its display come up back images. However, by working in this way it doesn't record in a permanent basis as a dashcam lens. Is possible to sort it out, so I can simultaneously record in the back and still working as a reversing camera, or technically it is impossible?

Any suggestion?