Please find the XML dictionary files at this link:
Select the version matching your FW version and you'll find the Italian XML dictionary file.
Put the English and Italian XML files into the same folder which will be the root folder for your tftp server (like tftpd32).
Then you'll need to configure the IP phone in Admin login, Advanced, Regional tab:
Dictionary Server Script: serv=tftp://aaa.bbb.ccc.ddd;d0=English; x0=spa50x_30x_en_v746.xml; d1=Italian;x1=spa50x_30x_It_v746.xml
Language Selection: Italian
Default Character Encoding: UTF-8
aaa.bbb.ccc.ddd is the IP address of your tftp server.
Hope this helps, and please do not hesitate to post if you need further assistance.
Sorry, I've followed theese instructions too, to upgrade italian language. But after all in the phone menu at the language option, i can choose english/italian, but after selecting Italian and save it, the phone lang don't change. I try to restart but i can see ever english language. Any suggestion?