Comment 7 for bug 357512

a simpler solution is to follow the instructions on this comment https://bugs.launchpad.net/wubi/+bug/252900/comments/9
otherwise, if you want to go the partitioning route, just use the live cd installer, it can do it just as well and you should already gave it :)
the program is called "editor de particiones" in spanish, but it should be something similar enough in italian.

any problems, post at the other bug (252900) instead, since it is where all the duplicates are being discussed.