Can't get information about active order number ($id_order)

[badyl]

Hi. I'm trying to get information about $id_order (number of active order) for my script. I've placed script in last step of the order, inside file "order-confirmation.tpl":

[removed]<!--
active_order_id = '{$id_order = Order::getOrderByCartId(intval($id_cart))}';
//-->
[removed]

It works fine, but only when I pay with "bankwire". When I try to use "cashondelivery" then $id_order is null. Maybe You can help? Do I need to place my script in other file? Or maybe there is other method to get $id_order than "getOrderByCartId"?