I have downloaded the italian keys and messages .properties files and copied according to instruction.
(cp *.properties opt/zimbra/tomcat/webapps/zimbra/WEB-INF/classes/msgs/
cp ZsMsg*.properties /opt/zimbra/conf/msgs/).
After tomcat restart both user web pages show the correct language selected by Firefox (it-it), but admin page is still in English.
I have tried to copy all the .properties file also in /opt/zimbra/conf/msgs/, with no luck.
What's my mistake?