replace innerHtml of the body in WebBrowser

Hey,
I am hosting a webbrowser control on my app.
I am doing some manipulation on the html of the webbrowser document by replacing the innerHtml of the document body (mshtml doc)
this all works great.
My problem is that the html that I am replacing with contains a start up jscript that normally accurs when the page is loading but when I insert the html to the document body by code that script does not run.
how can I force the page to rerender itself with the new html and run all the script that needs to run in the page load?

thanks,
kfs