Wow, I think you might have bought a big job, I have seen a Bluedot presentation where you hook electric brake rv's behind air brake semi trucks but the other way around? you may wind up converting the truck to air brakes.
The only guy that I know that may have a solution is Jack Mayer on the Escapees HDT forum..
Jack and Danielle Mayer
email Jack, let us know wht you come up with..
-blizz