As for Wilson himself, he has stated that he had a business relationship either with the Rock Creek Foundation, the Rock Creek Institute or the Rock Creek Company. Take your choice. He doesn't seem to have really worked with any of the three.
It's the Rock Creek Corporation, and Wilson is the "strategic advisor," whatever that is, according to his own CV.
http://www.mepc.org/public_asp/forums_chcs/archive.asp My guess is that Rock Creek Corporation is incorporated in DC, because it is based in DC. I've already checked Maryland and Virginia, and it's not incorporated in either of those.
I can't figure out how to access DC corporate information online - last time I wanted to get DC corporate information I had to drive into DC, but the corporate information office is cooperative and well organized.