Deploying a VSTO Click Once Add-in - don't forget your MIME Types!

I just wanted to make a note of this for future reference and to help any one that might be struggling with this in the future:

I have just created a simple Excel 2007 office add-in and I wanted to deploy it to a local server on my intranet and allow other users to click a url and install the application. Using the project properties page I configured the relevant server details and successfully published the add-on on to the server.

But when I navigated to the specified install url I received 403 error This website requires you to login. After searching the web for a suitable answer I finally stumbled upon the answer on this web site:

http://social.msdn.microsoft.com/Forums/en-MY/winformssetup/thread/10ee1ca1-b3ae-4a6f-98ba-125179b9e417

In summary, don't forget to configure the .'vsto' MIME type with 'application/x-ms-vsto' on the virtual directory containing the add-in.