insert new control into html

[Josh]

I am pulling html from the sql reporting services web service and inserting
it into a page of mine by using httpwebrequest method. I need to insert a
check box in a specific location within that HTML that I get from the web
service. Does anyone know how I can do this and have ASP.net render the
control.

I tried inserting an asp tag for the control in the html and placing this
code within the Page_prerender event but it will not render the control. any
ideas of how I can accomplish this?

Thanks