Silverlight video capture

I'm creating a new functionality in my website. An e-card sender.
http://www.game4tress.com/ecardsender.aspx
My problem is that i can initialize the webcam but i cannot set the image (source,...) inside an image control.
I've tryed several thinks and google about it, but i found nothing.
My main goal is to set the imgMain control source property to the video that is being displayed inside the Ellipse or directly set the webcamBrush to the imgMain.Source, so i could be able to show it to the user and send it to the desired e-mail
Can you please help?
My thanks in advanced

This is the code:

Dim webcamBrush As VideoBrush
Dim el As Ellipse

If Not CaptureDeviceConfiguration.RequestDeviceAccess() Then

Else
   Dim videoDevice = CaptureDeviceConfiguration.GetAvailableVideoCaptureDevices()

   Dim cs = New CaptureSource()
   cs.VideoCaptureDevice = videoDevice(0)
   webcamBrush = New VideoBrush
   webcamBrush.SetSource(cs)

   el = New Ellipse()
   el.Fill = webcamBrush
   el.Width = 400
   el.Height = 400
   cs.Start()