VS 2012 and attaching to IIS 7.5 process

I have a basic VS 2012 web application and I have it up and running fine on IIS 7.5, but when I try to attach to the w3wp.exe process it does not work.  The debug does not work.  If I push the play button in VS then the debug works as expected, but debug will not work with IIS.

Any help?

Thanks.