Special textbox format control

Hi!

I Need a Special textinput function that i not can find...

This is what i will do:

1. the TextBox text must have this Format: "##.####.###"

2. the Display ist "00.0000.000"

3. textinput (Keyboard Control): the user must only type in numbers, the Digits must stand there automaticly and the key must gon an if a "." is on the Position where a "." is

This is the XML Code for a normal TextBox:

<TextBox Height="23" HorizontalAlignment="Left" Margin="175,125,0,0" Name="textBox3" VerticalAlignment="Top" Width="166" MaxLength="10" HorizontalContentAlignment="Right" Canvas.Left="41" Canvas.Top="-4" />

Hav anyone a idea?

Best Regards

Bernd