Apply the 'Preferred Applications' gui lists to 'Removable Drives and Media'

In the 'Preferred Applications' window, users can choose through a gui drop-down list which application they want to use for that task. If the program is not listed, then the 'custom' option is also available which allows the user to enter a custom command. In the 'Removable Drives and Media' window, however, the user is forced to enter a custom command to change a specified program. The gui drop-down list style (with the 'custom' option) should be applied to this window as well, in order to make it easier for new users to change programs (from gthumb to f-spot for example).