In spite of considering the need to rebuild the rudder from scratch i decided to roll the leading edge in order to practice a bit.
Result is barely satisfactory. Lessons learned
1. get help. doing it alone is not trivial.
2. the 1 1/4 diameter pipe is not easy to find in italy and i resolved with a slightly bigger diameter....wrong decision as the rolling is not sufficient.
3. get a very sturdy pipe, otherwise the cleo will tear it apart. Gorilla tape may work, but i didn't have any.
4. work only if you have the right set up and tools. don't hurry