Adding extension mappings (also known as application mappings, or script mappings) to an IIS website or virtual directory is not supported by the current nant tasks available in Nant and Nant-Contrib. This project builds upon the existing iis nant tasks to add this capability.

The task call in your build script will look something like this:

<iisappmap vdirname="MyWebsite" extension=".jpg"
executable="C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_isapi.dll"
verbs="GET,POST" checkfileexists="false" />

See this blog post for more details:

http://persistall.com/archive/2007/06/11/nant-task-for-creating-iis-application-mappings.aspx