kchevalier

Create a stylesheet in your theme directory called ‘tinymce.css’ (for example). Add your desired link classes in there, like so:

a.myClass {}

Then, in your functions.php add the following:

function addTinyMCELinkClasses( $wp ) {
	$wp .= ',' . get_bloginfo('stylesheet_directory') . '/tinymce.css';
	return $wp;
}

if ( function_exists( 'add_filter' ) ) {
	add_filter( 'mce_css', 'addTinyMCELinkClasses' );
}

Hope that helps.