Parameter im Backend per URL übergeben

<?php...
function kunde() { ?>
    <div class="wrap">
        <h1>Kunde</h1>
        <?php $customers = Customer::getCustomers(); ?>
            <table border="0" class="wp-list-table widefat fixed striped">
            <thead>
                <tr>
                    <th>ID</th>
                    <th>Nachname</th>
                    <th>E-Mail</th>
                </tr>
            </thead>
            <tbody>
                <?php for ($i=0; $i<count( $customers ); $i++)    {    ?>                <tr>
                    <td><a href="/wp-admin/admin.php?page=kunde&kundeid=<?php echo $customers[$i]["id"]; ?>"><?php echo $customers[$i]["id"]; ?></a></td>
                    <td><a href="/wp-admin/admin.php?page=kunde&id=<?php echo $customers[$i]["id"]; ?>"><?php echo $customers[$i]["name"]; ?></a></td>
                    <td><a href="/wp-admin/admin.php?page=kunde&id=<?php echo $customers[$i]["id"]; ?>"><?php echo $customers[$i]["email"]; ?></a></td>
                </tr>
                <?php } ?>
            </tbody>
        </table>
        </div> <!-- .wrap -->
        <?php    }


function kunde() {    include( plugins_url() . '/login/customer.php' );}


// Adminmenu erweitern
function login_menu() {
    add_menu_page('kunde', 'kunde', 10, __FILE__, 'kunde');
    add_submenu_page(NULL, 'Kunde', 'Kunde', 10, 'kunde', 'kunde');
}


// Registrieren der WordPress-Hooks
add_action('admin_menu', 'login_menu');
?>