Upgrade path is the same if you are currently using the ML rom from this site.
A manual to make a backup?
You've asked it a few times, but the answer has already been given to you.
http://xiaomi.eu/community/index.php?posts/246193
Just click on backup and that's all. It will save all your local data. From apps to save games and e-mail settings.
but i don't see any backup of videos, music, notes, pics and calendar with local backup.