Hi i was just looking for this, i think he is talking about the content templates that come with FCK - there is an XML file under Providers/HtmlEditorProviders/FCKeditor/fcktemplates.xml
You need to provide your custom html inside the CDATA areas
Hope this helps albeit a year or so later - ill post how i got on and any gothas - Lee you may have covered this in a tutorial but if not ill post the method i used