So, now that my account is unlocked, I can help you finally.
I retrofitted the tpms on my F30 from 02/2014 successfully.
I tried many things.
But on the end only one combination worked.
I installed the control unit 6876227 together with the sensors 6856227.
The connection of the cables and the codings are the same for me.
In my attempts I also tried the sensors 6855539, but it also didn't work.
These sensors are for cars after 03/2014.
I hope this is helpful.