Thank you bourgeoa, I didn't answer before 'cause i was ill.
I tried to simply use the single drive folder, but it didn't work; so i run the manual firmware upgrade and it restore the web interface.
The data share failed, but I had only a backup on it so i recreate it by the interface and it now works.
There is only a last problem: i have just do the above operations and installed the "featurepacks manager" by highlevelbits, i haven't yet set anything else; sometimes the unit freezes (with the bottom led on) and i can only shutdown and reboot it…
I just see this, i will try if works: http://mybookworld.wikidot.com/forum/t-244219/my-book-world-network-drops-requiring-reboot