tracking code, need help.

[weblabs]

Hello,

I have, virtuemart 2.0.18a & Joomla! 2.5.9. ,  PHP VERSION: 5.2.17

I have this tracking code:

<iframe height='1' width='1' scrolling='no' marginheight='0' marginwidth='0' frameborder='0' src='http://xxx.xxxx.net/events/salecheck?amount=__ADD_SALE_VALUE__&campaign_unique=82e4b16d9&confirm=97701dfd23a8ae3f&description=__ADD_DESCRIPTION__&transaction_id=__ADD_TRANSACTION_ID__'></iframe>

Replace __ ADD_SALE_VALUE__ the total value of sale.
Replace __ ADD_TRANSACTION_ID__ with a unique id to identify the transaction.
Replace __ ADD_DESCRIPTION__ with an informative message about the transaction (eg. what products were sold).

Where do I put the code? and how select the order information.
Do not use payment processor like PayPal, i use VM Payment Standard.

The output of thank you page can be edited in /plugins/vmpayment/standard/standard.php (for standard payment method) i find the $html variable in plgVmConfirmedOrder($cart, $order) :

$order['details']['BT']->order_subtotal
$order['details']['BT']->order_number
order_number
$order['details']['BT']->order_total

but do not know if it is ok.

Thank you.