I'll try to describe the current situation we're dealing with.
We have made 2 HTML/CSS websites and the only difference between them is that one is on English and another one is on Italian language. The layout is the same.
We wanted to have option to add in both websites unlimited number of pages and, by what we read, we used WP and WP Network + WP MU Domain Mapping plugin and we managed to access both website from one WP.
WP is installed in English website, while Italian uses same files.
While English website works perfectly, Italian version somehow lost all Italian HTML pages, they are not accessible anymore. When I try to go to an page (i.e. http://www.company.it/contact_it.html), it gives me "Page not found" error even the "contact_it.html" page is already there, uploaded and doesn't have anything to do directly with WP. Also, the whole Italian navigation menu in Italian version of website is now replaced with English navigation menu, from English version of website.
I believe the issue has something to do with domain mapping or something that's related to that, but don't know exactly what.
Could you suggest us how to solve this issue since we really stuck there without any clue about what to do next?