iis6 multisite and permissions

The solution was not that there was a permissions issue.
Since iis6 doesn’t use .htaccess it required installing Ionics Isapi Rewriter

Enabled on the webserver you then insert essentially the same content as a the .htaccess file into an iirf.ini file in the root of the site you want and the content becomes available.
Much simpler than I was trying originally.