I've been looking for the same thing. There doesn't seem to be much information available online, and what is out there, isn't clear.
I'm pretty sure the Car 210111 will do it. I think the way it works is you peel back the door weatherstripping on both front door frames, drill and screw into the car body, then the weatherstripping goes back on and hides it.
I still don't know if I like the idea of drilling into the car. I'm thinking of trying to use heavy magnets.