In my response to Greg Paul a few years back, I mentioned a solution to the
issue that the Xu and Paul models offered, that if dislocation of the hips. I
offered that one could get the legs tucked up (as I'm sure the animals were
more capable of doing and mimicks avian flight position quite well without
inventing designs) and the vanes will operate aerodynamically better than in
other options.
http://i16.photobucket.com/albums/b1/Qilongia/microraptorposturesfigure.jpg
http://i16.photobucket.com/albums/b1/Qilongia/Microraptorlegpositions.jpg