Just to clarify for others:
In Kentico v6 if you want the style dropdown in CKEditor to be populated from a particular css style sheet you need to:
1. Add/edit the following lines in the /CMSAdminControls/CKEditor/config.js.
config.extraPlugins = 'CMSPlugins,stylesheetparser';
config.stylesSet = [];
The first line enables the stylesheetparser plugin. The second disables the built in CKEditor stylesheet.
2. Create a CSS style sheet in Kentico.
3. Set the editor style sheet property in Kentico.
You can do this at the site level in the Site properties or "You can change the stylesheet used in the editor by going to the properties of the editable region web part and setting the "HTML editor css stylesheet:" to your stylesheet. The stylesheet has to be added in
CMSSitemanager / Development / CSS Stylesheets. If the editor is used in some document property, this can be set in
CMSSiteManager / Development / Document types / / Fields / / CSS stylesheet."
Scott