Can I use php in the confirm page, the notification and the confirm email?
I want to adjust the response based on the input in the form and especially
I want to prevent to show the link to the payment process if the amount is 0.

Hi Linda,
You could alter the scripts but I think the easest way to do this would be to use jquery and disable the input if it's 0. The formbuilder won't submit a disabled input.

it is not a disabled input, it's an input with price: 0.00, but the result is the same.

Can you tell me how to write the jQuery, I started to learn the php, but that was not useful ????

This was the php I created.
<?php
$cart = (float) substr([_cart_total_], 3)*100;
echo $cart;
if ($cart!=0){ ?>
<a href="http://www.qtouch.nl/boek-qa-pay-test.php?i=accept&wd=[voornaam][achternaam]&wa=[_cart_total_]">Click to pay<BR><img src="http://www.qtouch.nl/Images/e-acceptgiro.jpg"></a>
<?php } ?>