paypal store receipt

[spid3r1987]

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...