The Bem is the module under the ICC the 4 large wiring plugs plug into.
They are colour coded. Yours probably Green and the one on the new icc is likely white/beige.
Swapping in the Premium/Dual Zone ICC wont get you acutal dual zone until you swap out (or reprogram the HIM) and install seperate mixer shafts and motors (Dash out job)
If you decide you want to do this I've got a set of shafts/dual zone HIM and Drivers side motor.