The autoleads cable will not allow any steering wheel interaction!
I had that exact cable on my old 3 series. Basically it is just a cable that converts BMW to din and back again. It does its job very well (saves you cutting lots of cable) but in order to control from the steering wheel you basically need a box that converts steering wheel to parrot control. Such as the connects2 or Audicom.
In my old car I had the Parrot CK3300 and the autoleads cable with nothing else. As for the oem look, well I didn't have it then but I put my microphone at the top of piller. Very subtle!
As far as I can tell the PC99-X21B steering harness adapter is used for people that want to replace their BMW stereo with something like a kenwood. Basically its a BMW > DIN cable.