On the left navigation panel,
go to the section Services Windows
Web Hosting > IIS Web Service, then click MIME
Types.
On the MIME
Types page, click Add MIME Type.
On the Add
MIME Type page, in the Extension
text box, enter the extension of the MIME type. For example, .doc.
In the MIME
Type Name text box, enter the name of the MIME type.
Click Add.