I've never done it, and I'm hoping I won't ever have to.
However, if you're really stuck (I googled it myself and found nothing useful), I might try emailing
the manufacturer at
They should know how the clips/anchors/brackets/whatever they're called are attached
to the outside of your van. They probably need model numbers and other specifics.
Alternately, you might try a local RV dealer near you. They might know.
Or my personal favorite, if your RV is registered with Roadtrek, you could email their
service people at firstname.lastname@example.org
assuming it was factory installed.
Make sure you include your VIN with your note.
If you can, post up anything you find out, when you get time. It might help someone else.