Wiring for GPS in my SLK R170?

[confused]

Hi

First post here so please be kind...

I'm about to wire a third-party DVD GPS unit + TMC into my SLK32. The previous owner had already replaced the APS30 with something a bit fancier so it's all a bit of a mess now behind the dash, and there aren't too many clues left about what's what. I need a wiring diagram, or at least the wire colours for:
- The GPS antenna (fitted on boot)
- The speed pulse from the ECU
- The reversing light signal
- Illumination, 'accessory' and 'main' power supply

Could anybody help me here?

Thanks!