New head unit Megane III, wont turn on/off when starting car

Hi all



I've installed a new head unit to my Megane III.



When I had the old standard unit, it would turn on when I turn on the car, and turn off when I open the door to get out of the car.



This unit doesn't do that. I have to manually turn it on/off.



Has anyone ever fitted a new head unit while retaining these functions on a Megane III ?



The tech who installed the head unit said "it couldn't be done".. but really??



thanks