Admin Order adding an extra product on add_line_item

So i manage to solve the problem myself after looking little more around, the hook is super poorly named. But it does the trick!
It fires after the order is created, so you can manipulate the order as you wish.

add_action('woocommerce_process_shop_order_meta', woocommerce_process_shop_order', 10, 2);
function woocommerce_process_shop_order ($post_id, $post) 
{
   global $woocommerce;
   $oOrder = new WC_Order($post_id);
   //add product
}