Hi Zolko and GlouGlou,
As you found out, the Twist parameter did not work with sketches that have more than one line segment.
Creating a join curve solves this by 1. creating a single curve and 2. moving the starting point to the top.
For those who do not know this trick and to get rid of the problem with the twist parameter, I have implemented Zolkos approach to reorder the line segments. The twist parameters will now reorder the line segments instead of the pole points of the lines. If you have 6 line segments, you can apply twists with a multiple of 60 degrees. I think this will work for most designs.
Check out the new version of the CurvedShapes Workbench.