Just reinstalled Z4Root, everything went smoothly with Permanent Root.
Now I should find the way to make the system use them instead of the standard ones.
KEYLAYOUT: should I rename the IT.KL file as "qwerty.kl" and cut away the original qwerty.kl?
KEYCHARS folder: should I rename the just-pasted it.kcm.bin as qwerty.kcm.bin?
Strange: there is also a qwerty2.kcm.bin
Edit. tried to rename the original qwerty.kl as qwertyNO (or whatever) to be able to name it.kl as qwerty.kl: Root Explorer crashes. I guess the system is using it while I try to rename it. What do you suggest? Will try a copy-paste to overwrite the original
Edit: did a copy-paste over those two original .kl and .bin files, after replacing their content with the italian ones. Result: on screen keyboard seems to function like ever but "backspace" makes "Documents to go" crash, external keyboard makes "Documents to go" crash as I type everything in.
Brought back the originals but Documents to go refuses to start up. Reboot, everything seems back to normal (noted that in "Device Storage" the command "Unmount" replaced the italian one.
At this point I do not have any idea on how to proceed further.