How do I do the impossible? Putting edge flanges on a sheet metal part that has a radiused base flange.

I know this isn't a normal practice in sheet metal.  But I know it can be done because I'm having to reverse engineer it.  The part is being mounted to the belly of an airplane.  I have a "C" shaped sheet metal part where the base of the part is bent with a 62" radius.  That's easy to create a base flange with these parameters.  The problem is when I try to put a edge flange on it from each side.  I've kinda worked around creating a sheet metal part by doing some features/mirroring.  But I can't flatten the part so what's the use then.  I've attached picture of the part's shape.  If anyone can figure out how to make this geometry in sheet metal and flatten it that would be great.
SolidworksSheet Metal