Adding a custom "Order Form" with clickbank

so the integration mod just asks for an ID of the product but how can i send them to a custom order form with my header image?

I think what you are refering to is the cbskin parameter?
If using clickbank in front you can use
http://1.NICKNAME.pay.clickbank.net/?cbskin=111

I think amember 3.2.3 had it in the product setting, but it was removed in the 4.x upgrade.
You can probably hack the clickbank plugin to pass this parameter.

David

Below this line:
$a->zipcode = $invoice->getZip();

Add this line:
$a->cbskin = 'your_form_id#';