trying to get an aux input

Anyone managed to get an aux input up near the HU? I got the standard tape deck with the OEM changer in the boot - so can't use the BMWPILA route. (Its a UK '02 models - speakers are driven from head unit - no amps).

There is a spare connector block on the back of the Tape Deck (right next to the CD connector block). Whats that for? Can it be adapted for an aux input?

Anyone help?? Wiring diagrams or anything...