I am in the same boat with my 135...
It can only be done through the dealer ($400)
I have been looking into this for a while and this is what I found.
If you have Comfort Acess:
The Key must be programmed at the Factory with your VIN, and then programmed to your car at the dealership.
If no CA then possibly is all I have heard, but have not researched as I do have CA.