paypal store receipt

just wondering, but when I go to pay via paypal
instead of store receipt number, it just says "store receipt"

is it possible to change the code in

includes/languages/english/modules/payment/paypal.php 

Line #55 : define('MODULE_PAYMENT_PAYPAL_PURCHASE_DESCRIPTION_ITEMNUM', 'Store Receipt');  

to reflect the order id??
like on my invoice.php

<h3 align = center>Invoice No <?php echo $oID ?></h3>

or something along these lines?
i know the customer gets a receipt etc, but my express wont work so IPN it is.
just wondered if it was possible to tweak the invoice.php to reflect either products purchased...

You can't put the order ID number in the payment transaction because the order ID number isn't assigned until after payment is received. That's an architectural flaw inherited from osCommerce.

ah, ok then, well its working on my invoice so i will leave that for now

guessing there's no way to list the products on IPN??
because i cant seem to get my express to work....placed a thread in paypal express thread but no response yet.