I have to explain some things and start from the beginning:
Cavalier has a "dumb" roof motor. Just open/close and nothing else. Easily recognisable by the thick red and brown wire (directly mounted to motor), connection to switch also by thick wires. Switch is everywhere the same grey (and ugly) push button switch.
Late Astra Mk3 (I don't know since when), Astra Mk4 (until MY2001) and Vectra B got the cleverer roof motor. Open/close and closure by central locking. Recognisable by the 12-pin connector (i.e. used at central locking unit) at the side. All again with the old, grey (and ugly) switch. Wires to switch are thin because they only switch ground connection as signal and no power as at Cavalier.
As I first dealed with the roof motor conversion I also wanted a more better looking switch - preferabely with illumination - but not the Omega B version with selector switch. So far so good.
Let's start with the conversion of the roof motor (same procedure equal to switch type):
1. Close sun roof!
2. Remove interior lights and roof cover, disconnect roof switch.
3. Remove roof motor: 2 Phillips screws M5x25 and one M6 hex nut.
4. Disconnect power supply (single pin connector) and ground connection (small screw in roof sheet metal behind sun visor).
5. Remove the screw marked with yellow circle (I don't know the sense of it...).
If you now fit the motor to the roof you will notice that it is slanted.
6. Dismantle cover of roof motor (4 Torx screws) and keep teeth gears where they are! Cut cover as shown in picture and at the red line in the picture. File edges and renew grease in motor (good opportunity now).
7. Install cover and insulate the uncovered parts with duct tape (as shown).
Now 2 ways are possible - with or without removing the metal bracket (I removed it).
8. Remove metal bracket or bend the part marked with green circle (see picture above) and remove the rubber buffer.
9. Install roof motor, use the 2 screws from item 3 and screw from item 5.
10. Rewire roof motor according to wiring diagram.
Picture of fitted motor:
Now it's time to decide!
Which switch shall it be?
The grey ugly one? Then use your old roof cover. Or the "premium version" with illumination?
If you want to have the better one this will cost some efforts and is a little bit tricky!
Two problems occur: illumination of switch is unforeseen in original and roof motor is controlled by switched ground.
1. Buy roof cover from Zafira A part number 9184576 (approx. 15 GBP) and a window lifter switch from passenger side of a Corsa C together with its 4-pin connector.
Ignore the two-button-switch.
2. Dismantle window lifter switch, resolder the illumination LED and solder it the other way round (best time to fit LED with different color!).
3. Connect as follows: switch pin 1 to ground, pin 2 to roof pin 2, pin 3 to roof pin 4 and pin 4 to ignition live wire (the same as for roof motor).
4. File the slotted holes for mounting until it fits to screw holes in roof. The back part is held by the weatherstrip.
Now you are done!