The 4 wires going to T6j connect directly, and only, to the coming home button on the light switch. T6j/1 goes to earth. I'm not dead sure where T6j/4 and T6j/2 come from but one supplies the switch with the power for the small light that is permanently on (similar to the light for the main light switch) the other, I would assume, comes from light sensor to tell the set up whether its day or night. T6j/3 goes to the pin 12 of connector E. With Marc's wiring, he's basically bypassed the switch and connected earth straight to E12, thus enabling a permanent, non-switched connection.
I've retro fitted a new light switch with the coming home button and made up the wiring the same as in the diagram. I've got Zenon's and with the coming and leaving home functions activated in Vagcom, the features work fine when the coming home button on the light switch is pressed on. I can't see the difference between having the button and not so in theory, the function should work. But there again, I haven't managed to get the auto lights working so I'm no expert!