Cruise Control Installation: Citroen C4 2.5 TDI

I bought a steering column switch with GRA and a 15 cm wiring harness from a recycling company at a very low price. Now my question: The wiring harness has 6 pins. How should these be connected? I've found out the following:
Contact 1 on the GRA (Gear Range Actuator) terminal is connected to pin 30 on the control unit.
Contact 2 on the GRA (Grounding Relay Assembly) terminal is connected to pin 45 on the control unit.
Contact point 3 on the GRA switch is connected to pin 48 on the control unit.
Contact 4 on the GRA switch is connected to pin 24 on the control unit.
Contact 5 on the GRA terminal is connected to fuse 64 (switching mechanism).
Contact 5 on the GRA terminal block is connected to the transmission control unit (automatic transmission).
Contact 6 on the GRA (Gear Range Actuator) connector is connected to pin 24 on the control unit.

Then unlock it using code 11463.

'What seems a bit strange to me is that contacts 4 and 6 are both connected to pin 24. Where does contact 5 connect to on the automatic transmission control unit? Is this guide correct so far? Does anyone have a wiring diagram or a pinout for it? MKB: AAT, Control Unit Number: Bosch 0 281 001 255/256, Part Number: 4A0 907 401 F.'

Take a look at this page. It has lots of wiring diagrams. They are for the original Quattro, Audi 100/200 Type 44, Audi 100 Type C4, and Audi 80 Type B4. Unfortunately, none of them are useful to me because the engine control unit is different on my A6 C4.

http://www.isham-research.com/quattro/wiring/

'This weekend, I finally connected my GRA (Gearbox Retrofit Adapter). It worked! I used a soldering iron, created a custom wiring harness, and connected the pins according to the instructions. All the pins were loose and needed to be reconnected. I took an old Audi wiring harness from a car radio and removed the connectors. For the automatic transmission control unit, I wired pin 5 so that there is 12V on the line when the gear selector is in 'D', and it's de-energized in positions 'N', 'R', or 'P'. I then went to the dealership and had them enter the unlock code. The technician said he needed to check if the code was correct. He concluded that retrofitting a GRA on a C4 TDI isn't as simple as it seems. I then went to another dealership, entered the code, and it worked. When unlocking, it's important to ensure the GRA is active and the gear selector is in 'D' for an automatic transmission. Now I have a GRA for 25 EUR. I hope this guide helps someone else. All information is based on my best knowledge, but I offer no guarantee.'

When I mention pin 5, I'm referring to contact 5 on the switch that connects to the transmission control unit.