I correct the partial language file you created so that it follows the correct naming.
Send me a private email from
http://multicommander.com/contact and I will send you a Submit key and you can submit changes so they are added automatically.
To install the MC_LangPack_it.zip do this..
First delete this folder (unpacked language files that the language editor creates..)
C:\Users\<
username>\AppData\Roaming\MultiCommander\UserData\Languages
Then put MC_LangPack_it.zip in <MCInstall>\Languages
remove <MCInstall>\Config\SupportedLanguages.xml
( a new file will be generated in C:\Users\<
username>\AppData\Roaming\MultiCommander\UserData\Languages and it will now use that when starting to know what languages are supported )
Restart MC. go to core setting and change language to Italian.