I am having difficulty lofting a bend in the middle of constructing a part.  The Idea here is that I make an inflated structure with weldment features.  Then I produce some sketch geometry from the inflated structure geometry to make a skin that goes over the inflated structure.  The skin is really coated fabric, but we unfold the patterns with sheet metal functionality.  It does not seem possible to use sheet metal functionality properly when I am this far into a part model.  I tried using Sketch blocks produced from the model to make a second part, and then use these as an assembly.  Sketch blocks did not seem to work for lofted bends either.  Any Ideas out there.  See the attached model if you are interested.  I am attempting to loft between the grey box, and the  sketch that is inbetween the first two arches.  Note that I have a sketch that is converted off the edge of the grey box.

Jack