Hi there, mmmm... I think that your scenario is not possible.
Investigating about your question I found this very useful article http://msdn.microsoft.com/en-us/library/cc221359(v=vs.95).aspx
In your case, you can put the iframe on your aspx page and call it using a third party control like this
] or using the webbrowser control of silverlight :)
In your code I see that you want to show a pdf, so I give you some solutions to show them:http://silverlightpdf.codeplex.com/
] Use this with your code above ;)
Hope it helps in any way