Add admin separator to admin menu

gistfile1.php

add_action( 'admin_init', 'add_sep' );
function add_sep() {

    if ( ! is_admin() )
        return false;

    global $menu;
    $sep = $menu[4]; // that's the default separator
    $pos = 6; // change it for the desired position
    $menu = array_merge(
        array_slice( $menu, 0, $pos ),
        array( $sep ),
        array_slice( $menu, $pos + 1, -1)
    );
    $menu[ $pos - 1 ][4] .= ' menu-top-last';
    $menu[ $pos + 1 ][4] .= ' menu-top-first';

}