OpenAuth.RequestAuthentication & localized provider site

When I call

OpenAuth.RequestAuthentication("facebook", redirectUrl);

it always redirects to the English login page of Facebook. How can the user land on a localized login page, say, the Portuguese login page of Facebook?

( I got in Global.asax.cs :

 protected void Application_Start(object sender, EventArgs e)
        {
           // ...
            System.Threading.Thread.CurrentThread.CurrentUICulture = System.Globalization.CultureInfo.CreateSpecificCulture("pt-BR");
            System.Threading.Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.CreateSpecificCulture("pt-BR");
        }

)

Thanks,

Gustavo