I believe you will need to create a plugin to make this work. An example can be found here: http://ckeditor.com/forums/CKEditor-3.x/Custom-drop-down
Additionally there seems to be addOn for CKeditor located here: http://ckeditor.com/addon/strinsert
This addOn adds strings to your content but you may be able to look at the code and figure how to make it add stylings.