run web app in visual studio 2010 using local iis server

I want to be able to debug a C# 2010 web form application that runs using the local iis server. I have my breakpoints set in the application, but the code never stops at those breakpoints. ( I want to do this type of debugging since the application is going to run under iis on a test server and then in production.)

When I run the web form 2010 application using cassini in the debug mode, all the break points are hit and the code runs with no problems.

Thus can you tell me what I need to do to be able to debug my web form app 2010 using the local iis server so that I can hit the breakpoints I have set to see what is wrong with the application?