If you own HTML Editor 3 you can use it to customize the two html editor instances in the two PCMS Builder generated pages named ‘contents_update.php’ and ‘contents_insert.php’ found inside the admin_cms folder. Instructions for adding your own custom styles to the editors is documented in the HTML Editor 3 Getting Started Guide.
For my purposes I usually create a separate style sheet with the class styles I want to import into HTML Editor 3. Name it ckeditor.css or something semantic. Then I import it into HTML Editor 3 and designate my custom classes to specific html tags for the editor to reference. Save your preset after modding the first editor, and you can simply apply the preset to the second editor instance in a matter of seconds. Done.
Just tried it again and it works like a charm. Now the end user has a list of pre determined styles that I know will fit the look and feel of the site. In the Styles pull down, the list of custom styles do take on their own attributes so they're easier to identity. Being a bit of a control freak, I usually strip out most of the extraneous text styling doo-dads in the editor and leave only the bare essentials - similar to Basecamp's text editor. Then coerce (or force) the end user into only using styles that will fit the hierarchy of the page design.
Not sure if this is what you guys are tying to do, but for what its worth...