Thanks ttmcmurry for the answer!
I've tried the scandisk of the firmware 1.08 to see if it was one drive failed. The scandisk worked well and the indicator arrived at 100%, but it stopped at 100% and for 2 hours just the right disk was working. Since the web interface became unreachable, after 2 hours and something i shut down with the front button.
I've tried also a factory reset with the button on the back of the unit, but with no luck.
Now i've decided to try to format again the raid1 (after i backed up my data, of course) to see if it was a bad-bulit raid array. The format is taking place right now.
Can you explain me what you mean by "more than one share"?
As soon as it ends the format i'll try to see if it accept again the shares, if not i'll post the screenshot. But i can tell you that for the time it worked, nothing changed in the device info page: just one volume, free space and occupied space was right and plausible and the two phisical drives was seen correctly. No printer and no ups connected and, also, no network configuration change.