You can enable the CKEditor's "source" button, that allows you to edit the html tags directly :
['Source'],
['Bold','Italic','Underline','Strike'],
['Font','FontSize'],
['TextColor','BGColor'],
['Link','Unlink'],
'/',
['JustifyLeft','JustifyCenter','JustifyRight','JustifyBlock'],
['NumberedList','BulletedList','-','Outdent','Indent','Blockquote'],
['Image','Flash','Table','HorizontalRule','Smiley','SpecialChar'],
['RemoveFormat', 'Maximize']