If you are trying to add video chat using 3rd party chat softwares User plane is a good option..
They have a free edition with ads which you can easily add to your website..
Also i advice you to use the Silverlight Application for video Conferencing:
I would like to suggest you to check the link below for the sample:
Here is a similar http://forums.silverlight.net/forums/t/188896.aspx which provides some solutions for the same issue ,please check it and see whether it helps.
Hope it can help you.