Daft question re door mirrors

[QBee]

I am trying to update my TVR electric, heated door mirrors from factory Citroen CX mirrors to factory VW Corrado mirrors (as supplied on all TVRs from 2001 onwards).

Got the mirrors, got the adaptors to fix them to the door, got more wires than I was expecting.
The Citroen mirrors have 7 wires.
The Corrado mirrors have 8 wires.

We can ignore the two heated element wires and the two door opener solenoid wires - they happen on both.
As anyone who knows TVRs knows, all TVRs from about 1997 onwards have a door opener button on the underside of the mirror.

The three Citroen wires - one controls up/down, one controls left/right, and the third is a common supply from the joystick switch.

Wiring diagram here:



The four Corrado wires are supposed to connect as in this Cerbera wiring diagram, using an ECU:



Am I being simple, or downright stupid, or is there a chance that one/two BMW E46 mirror ECUs would do the trick and connect up my Corrado mirrors? These are readily available, whereas the Cerbera units are as rare as (rusty) hens teeth. Obviously I would need to use the services of an electrician who knows WTF he's doing, but I have one of those to hand.

Any help would be most gratefully received...

[helix402]

I'm not sure the BMW parts would help. I think they would just add another component to wire into the system.

[QBee]

Yes, having posted I have cleared my thinking (with my electrician's help) - I should look for a VW control unit I think