Just hooked up my X5 (2000 4.4I with DSP 4:3 nav screen and MKII computer) and I believe I must have done something wrong as I now canot operate my Sat nav and radio with the Sat nav buttons.

I can:

Switch off the radio
Control the radio and phone with the steering wheel
Start up sat nav using voice and use the sat nav rotation, but no pressbutton.
All the rest of the buttons, on the sat nav, do not now do anything. the steering wheel is fully functional though.

Any Idea what I should do?

Yes I know A little bit of knowledge is dangerous!! and I seem to be finding out to my horror!

If you say join Hck the I-bus well I have tried that but it's a nightmare to get into as its knocked me back once, probably as I only have a hotmail address! and I'm still waiting for the reply to my latest try.