Default search in PS 1.5.4.1

[mr_smiley]

Hello. In the shop we do not remove items that are no longer available from the supplier. We remove the checkbox "available now" and "show price". On the product at this time there is a picture "Not available for order." When a customer comes into the category of goods, any goods that are not available for order at the end of the list.

When using the sort by name, price, products are not available for order and remain at the end of the list. Made it in the file

classes\Category.php

$sql .= ' ORDER BY p.`available_for_order` DESC, ' .(isset($order_by_prefix) ? $order_by_prefix.'.' : '').'`'.pSQL($order_by).'` '.pSQL($order_way).'
            LIMIT '.(((int)$p - 1) * (int)$n).','.(int)$n;

I would like to see this sort persisted when using "Search" on the site, as well as using the module "Advanced Search 4".
Thank U. Willing to pay for the work to finalize the functional.