Catching events within an iFrame loaded within a Silverlight page

I have a Silverlight page that loads an iFrame. Within that iFrame is Javascript code that is generated by the pega tool from http://pdn.pega.com/

The generated Javascript code basically creates a form with a textbox and a few buttons. so in the end when the Silverlight application loads I have a list box on the left side of the Silverlight page. The iframe also within the Silverlight page on its right side which has this generated form. When I select something in the list box. I need to pass that value into the 开发者_如何学编程iframe and further down into an input parameter in the generated code. This part I can get to work. However I need to also trap the button click event that is within this generated form and send that back to the Silverlight application. Any ideas on how to accomplish this? Cant change the generated code.