After 100.000.000 test, I've find the right string for SQLExpress:
<add name="NopSqlExpressDB" connectionString="Data Source=.\SQLExpress;attachdbfilename=|DataDirectory|NopCommerce.mdf;integrated security=SSPI;Persist Security Info=False;" />
Ok, Now is working.
I've also generated SQL for Italian Language. Where I can send SQL file?
Bye