Hi bro, I managed to "upgrade" my 4-spoke Non-Multifunction steering to the 3-spoke sport steering. For you to activate the multifunction in your 3 spoke steering, you just need to retrofit a wire from the steering to the DME. It is as written in the link given both by bro bmw7833 and wutty. I think the technician might be giving you some false info lah bro.
For your info, my car is 2001 320 Six Potter Japan spec.
Before with 4 spoke steering :-
After with 3-spoke steering