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
...