With help from this great tutorial https://coronalabs.com/blog/2015/02/24/tutorial-inputting-text-on-windows-phone-8/ I managed to make a login input form and it works great.
The only thing that is not working are custom fonts on the native form.
Does Corona not support this or is it a bug?
Please take a look at the screenshot.
The same custom font works in other parts of the app.
And here is the InputForm.xaml (it is the same as from your example, only tried to change the font).
\<UserControl x:Class="Fun\_Football\_Europe\_2016.InputForm" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" FontFamily="/Fun Football Europe 2016;component/Assets/Corona/DESIB\_\_\_.ttf#Designer Block" FontSize="36" Foreground="{StaticResource PhoneForegroundBrush}" d:DesignWidth="488.955" Height="364.418"\> \<StackPanel Margin="0,-100,0,71"\> \<StackPanel.Background\> \<LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0"\> \<GradientStop Color="Black" Offset="1"/\> \<GradientStop Color="#FF28439C"/\> \</LinearGradientBrush\> \</StackPanel.Background\> \<StackPanel Margin="10,10,10,10" Height="381"\> \<TextBlock x:Name="fUsernameLabel" TextWrapping="Wrap" Text="Username" FontFamily="/Fun Football Europe 2016;component/Assets/Corona/DESIB\_\_\_.ttf#Designer Block" FontSize="36"/\> \<TextBox x:Name="fUsernameTextBox" InputScope="Default" FontSize="36"/\> \<TextBlock x:Name="fPasswordLabel" TextWrapping="Wrap" Text="Password" FontFamily="/Fun Football Europe 2016;component/Assets/Corona/DESIB\_\_\_.ttf#Designer Block" FontSize="36"/\> \<PasswordBox x:Name="fPasswordTextBox" FontSize="36"/\> \<StackPanel VerticalAlignment="Top" Orientation="Horizontal" HorizontalAlignment="Center"\> \<Button x:Name="fOkayButton" Content="Okay" Click="OkayButton\_Click" FontFamily="/Fun Football Europe 2016;component/Assets/Corona/DESIB\_\_\_.ttf#Designer Block" FontSize="36"/\> \<Button x:Name="fCancelButton" Content="Cancel" Click="CancelButton\_Click" FontFamily="/Fun Football Europe 2016;component/Assets/Corona/DESIB\_\_\_.ttf#Designer Block" FontSize="36"/\> \</StackPanel\> \</StackPanel\> \</StackPanel\> \</UserControl\>
On the phone:
In Visual Studio design the font is OK: