Make custom url in Magento Modul in Admin

<?php
My actual Url is
"http://localhost/magento/index.php/admin_metal/adminhtml_metalbackend/index/key/f64c498b4c19e35795ce97188cd3c3ee/";

we create Url by Pragmatically :
echo Mage::helper("adminhtml")->getUrl("metal/adminhtml_metalbackend");

?>