You can edit your Server's MIME files from the Mime Types page.
MIME (Multi-purpose Internet Mail Extension) types control the types of multimedia files your mail system supports. MIME types also specify the file extensions that belong to specific server file types. For example it helps to designate which files are CGI programs.
You don’t need to create a separate MIME types file for each virtual server. Instead, you create as many MIME types files as you need and associate these files with a virtual server. The mime.types file, exists by default on the server, and cannot be deleted. This file can be the absolute path.
Access the Server Manager and click the Preferences tab.
Click the MIME Types link.
Make the desired changes and click OK.
For more information, see the MIME Types page in the online help and Chapter 14, Using Virtual Servers.