Example 4 - Adding a new document type and file type icon
To add a document type and type icon, do the following:
In the Program Files\Common Files\Microsoft Shared\web server extensions\50\Templates\1033\xml directory, open DOCICON.XML.
In the middle of the file, find the ByExtension section.
For the sake of example, we will add a wav file type and an icon to represent what kind of file it is. Add a line like the following:
<Mapping Key="wav" Value="icwav.gif"/>
In the Program Files\Common Files\Microsoft Shared\web server extensions\50\Templates\1033\Images directory, add an appropriate icon and call it "icwav.gif".
Restart Microsoft Internet Information Services (IIS).
Create a new subweb.
All sites created from now on will display icwav.gif in document libraries for files that have the .wav extension.