WPF - XAML Page with virtual keyboard

page.xaml

<Page x:Class="RegistrationKiosk.FirstName"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      xmlns:TermControls="clr-namespace:TermControls;assembly=TermControls"
      xmlns:adorners="http://gu.se/Adorners"
      mc:Ignorable="d" 
      d:DesignHeight="{Binding SystemParameters.PrimaryScreenHeight }" d:DesignWidth="{Binding SystemParameters.PrimaryScreenWidth }"
	Title="FirstName">

    <Grid>
        <Grid.Background>
            <ImageBrush ImageSource="Images/teller-background.gif" >
            </ImageBrush>
        </Grid.Background>

        <Image 
            Height="51" 
            Width="500" 
            VerticalAlignment="Top" 
            Source="Images/EnterFirstName.png" 
            Margin="88,59,89,0"/>
        
        <TextBox 
            Text="{Binding Text, ElementName=OnScreenKeyboard}" 
            FontSize="20"
            FontFamily="Adelle"
            TextChanged="TbFirstName_OnTextChanged" 
             GotFocus="TbFirstName_OnGotFocus"
            Name="TbFirstName" Margin="88,152,89,0" 
            VerticalAlignment="Top" 
            HorizontalAlignment="Center" 
            Height="30" 
            Width="500" />
        
        <TermControls:OnScreenKeyboard 
            x:Name="OnScreenKeyboard"  
            Height="100" 
            Width="500" 
            VerticalAlignment="Center" 
            Margin="88,182,89,61" 
            Background="Black" />
        
        <Label 
               Style="{StaticResource Status}"
               Content="" 
               Name="LblStatus" 
               HorizontalAlignment="Center" 
               Margin="350,110,317,0" 
               VerticalAlignment="Top"/>
        
    </Grid>
</Page>