WebView does not open popup - Windows Phone 8.1

I'm trying to get authentication for a URL, so check it out. But on the site, which I am trying to authenticate, it is possible to log in with facebook, but when using this alternative, instead of the facebook login / authorization page it appears in the component itself (WebView) it calls the default OS browser, authentication does not work. My question is, how do I open this facebook popup on the component itself? Thank you.

C #

private void wvwTeste_Loaded(object sender, RoutedEventArgs e)
{
    string _clientId = "123456";
    wvwTeste.Navigate(new Uri("https://api.teste.com/oauth/?" +
                                                    "response_type=code&" +
                                                    "redirect_uri=https://localhost/&" +
                                                    "client_id=" + _clientId + "&" +
                                                    "scope=read_public,write_public&" +
                                                    "state=768uyFys", UriKind.RelativeOrAbsolute));
}

XAML:

<Grid>
    <WebView x:Name="wvwTeste"
             HorizontalAlignment="Stretch"
             VerticalAlignment="Stretch"
             ScrollViewer.ZoomMode="Disabled"
             ScrollViewer.VerticalScrollBarVisibility="Disabled"
             Visibility="Visible" 
             NavigationCompleted="wvwTeste_NavigationCompleted" 
             Loaded="wvwTeste_Loaded" />
</Grid>