You should leave the <globalization element as it was and just use these to force a site culture:

<add key="UseCultureOverride" value="true" />
<add key="site1culture" value="it-IT" />
<add key="site1uiculture" value="it-IT" />

however if it is a multi site installation note that the 1 is the site id, so if the site id is not 1 for your site then you need to change it, ie if site id is 2 then:

<add key="UseCultureOverride" value="true" />
<add key="site2culture" value="it-IT" />
<add key="site2uiculture" value="it-IT" />

See also Localization