Retro fit Reverse camera

[daviesbike]

I started rabbeting on in another thread so thought i would start another one,

so i bought this camera http://www.ebay.co.uk/itm/Rear-View-...#ht_2571wt_698

im going to buy this cable
http://www.ebay.co.uk/itm/CT29AU02-A...ht_3148wt_1022

if i wire it all up and take the power from the reverse lights then it will only power on when in reverse and maybe code the MMi so that when reverse is engaged then it switches to Av 1 ( Question can this be done ? )

or do i wire it up live so that i can switch to Av 1 anytime when driving and see whats behind ?

has any one done this before ?