Disable internal pingbacks

Hi! 🙂
I’m using WP 3.2.1 and a custom theme of mine. I’d like to disable internal pingbacks (they shouldn’t appear in comments neither in dashboard within recent comments). I searched a bit and found this code (functions.php)

function disable_internal_pingbacks( &$links ) {
    $home = get_option( 'home' );
    foreach ( $links as $l => $link )
        if ( 0 === strpos( $link, $home ) )
            unset($links[$l]);
}

add_action( 'pre_ping', 'disable_internal_pingbacks' );

Anyway it changes nothing… pingbacks still appear within comments.. can you help me?

Thanks in advance,
Lorenzo