Hi, I have just tried:

$Mandatory_Fields= '*' . join( '*',
                         'Customer Name',
                         'Customer Email',
                         'Phone Number',
                         'Payment Method',
                         'BillingAddressLine1',
                         'BillingCity',
                         'BillingPostCode',
                         param( 'payMethods' ) eq 'Credit Card' ?
                         qw( CardStartDate
                             CardIssueNo
                             CardSecurityCode ) :
                         () );
[download]

But I am getting an internal server error when trying it out. Any ideas please?