Ultimate Facebook - Map WordPress profile to Facebook (Import Problem)

Map WordPress profile to Facebook

when a new user registers with Facebook, the data is imported, sometimes in Italian, sometimes in English (although users are Italian with facebook italian profile)

I import the birthday date, that's a big problem.

In fact, checking the database wordpress, some dates are stored in the format dd/mm/yyyy and others in the format mm/dd/yyyy.

My goal is to unify the format, it's not important which one.

Solutions?