can't remove default dupal's styles from style drop down menu.

hi all.
I need to customize the style drop down menù.
I copied the ckeditor.styles.js to my theme path, and i selected 'use theme ckeditor.styles.css' in css option.
The file in theme directory works, i can add my personal styles.

But in the style menù there are many styles (they seem drupal styles, like div.messages, div.error, div.view, or span.sortableListSpan, that i can't remove. I need to eliminate them.
I searched for a file defining that styles in the module directory, but i didn't find anithing.

How can eliminate that styles? where there are defined?

Thanks in advance.

Edubacco