From what I have found out, if it is a DKW, it's based on the electrocar mentioned ower here. Rasmussen mounted the 40 ccm engine on the side. The twostroker was just a helpengine for the elektroengine, but this extra power gave the car the oppertunity to climb a lot steaper hills. In other words a early hybrid. In the small pieces of text I have found, this Bergsteiger, are mentioned too only have reach the prototype stadium, not knowing how many cars actually built.
When talking about doors, the driver had doors both sides, but the passanger only on the left side.
I'm sorry, but this is all I can find about this vehicle.