Hi Marco,
1) Please update your parent theme.
2) Download the .po file from that once the download has finished.
3) Add your translations to that and remove uncheck any strings marked as fuzzy. Save that, then compile a .mo file. Upload both to your child theme /languages/
folder replacing the existing.
I have checked the supplied translation file, the theme options strings are ready for translation. But you actually need to add the Italian translation. Ex:
#: includes/sf-options.php:1171
#, fuzzy
msgid "Header Options"
msgstr "Opzione Tema"
You need to change that to your own translation, it’s not automatic.
Thanks.