I was looking into this as well. I think there are certain options that are required in order for the streaming BT to become active with coding. I read that on the bimmertech site. I'm in the same boat but haven't taken the plunge to code my own car yet. You have to have these options installed on your car for it to work.
6AC, 6AE, 6NH (all three) or
6NH and 609 (both)
Check the VIN decoder site to see what options were on your car from the factory.
http://bimmer.work