Issue swapping a standard stalk for cruise control stalk

[steham]

Just a quickie.
I'm in the process of retrofitting cruise control.
I took off the bog standard stalk, and got hold of a 3 series cruise control stalk.
I haven't yet coded it all in, that for next weekend (or when my protocols dongle arrives.

Now, this morning, first time I've gone to use the car, I e noticed that none of the controls on the steering wheel work. I plugged everything in, but am wondering why the steering wheel controls aren't working. Have I done something wrong, or is there something else I need to do?