I got around to talking to the people about the electric windows, and they think if I reverse the wires to the motor, the passenger side switch will work correctly. I think if I reverse the wires, the driver's side will work incorrectly, but I guess I'll try it. I have a feeling that I'm going to end up with multimeter in hand figuring out how this all works.
In the evening, I pulled the passenger door apart on the van, and wired it up as suggested. As I thought, the passenger side worked, but the driver's side was then reversed. Then John came over and took us to dinner.