I think there was a thread a long while ago about fitting alternative radios, blanking plates and so forth. From memory some kind of harness was required but I don't know if anyone got the steering controls to work.
If you search the forum you should find a few pointers - this seems to be the font of all (ok most) sensible (ok usually) info on Cromas. Don't forget to post back to let us know what happens and what you had to do.