If you are using this "look and feel"
The Reflection Ribbon
On the Session ribbon, from the Transfer group, click the Transfer Settings launcher:
The Reflection Browser
On the Reflection menu, choose Tools and then File Transfer. In the Transfer dialog box, click the Settings button.
Type an extension, and then choose a transfer type to associate with that extension.
Type the extension for the transfer method. The limit is five characters, or type "<>" to associate a file with no extension to a transfer type.
Select a transfer type to associate with the extension in the Extension box.
If you are unsure which transfer type to associate with an extension, use Scan. Reflection uses the proper transfer type after "scanning" the file being transferred.
Auto-Detect Tab (Transfer Settings Dialog Box)