There's nothing available rearward of the battery with adequate capacity to charge your van. It's not a particularly hard job... check out the DIY Trailer Wiring post I made at the other place:
http://www.jeepgarage.org/showthread.php?p=1072958
I must get around to re-linking all the images Photofukdit made unavailable. Give me a day or two, or PM me.
Cheers,
Steve