Defining a cache manifest file in ASP.NET

When using the cache manifest file in ASP.NET, can I just add a standard text file called as app.manifest? (which then links to html on each corresponding page).

Or are there other considerations (such as the mime type) that require a more complex approach?

In this approach: http://stephenwalther.com/blog/archive/2011/01/26/creating-html5-offline-web-applications-with-asp-net.aspx , then Stephen Walter sets the manifest as a handler. Should I really do this in ASP.NET, or is there an “easier” way in ASP.NET? Just the pursuit of less code!

Thank.