What about adding a new instance of HTML Editor?
I have two custom additional fields in my Products_Update.php document. I've tried to use HTML Editor to add that function to these two fields and end up with white space on the fields with no editing/clicking abilities.
There seems to be a conflict between iRite and HTMLEditor, as iRite was used with PowerStore, but HTML Editor is required to add. (I realize I can edit existing iRite with HTML Editor...)