Damian,
Final Cut Pro doesn't have any built-in support for authoring, editing, or previewing .scc files.
One possible software you could use for this task is our CaptionTrack plug-in (
http://www.eegent.com/software/caption-track/). CaptionTrack enables you to edit closed captioning data right in your Final Cut timeline, and it can import captions from/export captions to an .scc file.
The following video tutorial demonstrates how you would use CaptionTrack to import captions from an existing .scc file, make your desired edits, and then export the edited captions to a new .scc file:
Hope this helps,
Samuel Windwer
EEG Enterprises, Inc.
