Mask "Confirm" button in step 3 checkout page

I currently have 3 payment methods available on my test site : cheque (works fine), Paypal (works fine) and Credit Card using a contributed payment module (starting to work....). My problem is with the "confirm" button at the bottom of the page : I don't want this with credit card payments because to finalise the order, the customer has to click on one of three buttons which are images of the different credit cards I can accept. The customer is then redirected to the bank's server where he can enter his credit card info. If the customer clicks on the "confirm" button the bank's server rejects the request so I need to mask the button but only on the credit card payment page, NOT on the cheque and Paypal payments pages. Someone has suggested I insert this code into includes/template_default/templates/MYCUSTOM/tpl_checkout_confirmation.php :

if (isset($$_SESSION['payment']->form_action_url)) {
$form_action_url = $$_SESSION['payment']->form_action_url;
} else {
$form_action_url = zen_href_link(FILENAME_CHECKOUT_PROCESS, '', 'SSL');
}

However, I'm not sure where to put it, whether it replaces some other code and more importantly whether it won't result in the confirm button being masked everywhere.

Any ideas?

Cheers

Pete

Solved, it wasn't the right code.