2 December 2011 at 9:57pm
Just press that little blue button (in the editor toolbar, to the right of the anchor). It will give you the HTML popup so you can edit it. All HTML you enter in the CMS editor, is stored in the database.
All other SilverStripe HTML can be found in your themes/... /templates folder.
If this doesn't answer your question, then I probably don't understand you correctly... :-(