I am trying to use SolidWorks to design a special magnet for MRI called a transverse gradient axis.  This involves cutting a spiral groove into a cylindrical shell of conductor.  The resulting path produces a magnetic field that is used for spatial encoding in MRI.

When trying to sweep a sketch around a cylindrical face using the Swept Cut feature, there is a problem when the curve changes azimuthal direction.  The SolidWorks algorithm seems to flip the sketch frame upside down each time it has to move in the opposite theta direction.  Very annoying.  I am attaching a zipped directory with the SolidWorks drawing, curve and the captured movie showing the problem.  ANY HELP WOULD BE VERY MUCH APPRECIATED!