I have custom custom field named "documentId" for a product. When a client singup for a service and fills in this field, I want the domain name to be set to this "documentId" value. I tried do this using action hook PreModuleCreate http://docs.whmcs.com/Hooks:Products...reModuleCreate but te below code is not working.
$vars['params']['domain'] = $vars['params']['customfields']['documentId'];
Any idea what I am doing wrong?