Recurring billing variable amount without storing credit card information

Question

I have implemented few payment websites using PayPal Standard, PayPal Website Pro, PayPal Express and Authorize.Net.

Now I'm implementing a website which requires recurring billing. My only problem is variable amount, since I do not store credit card information, and amount is not fixed in each cycle.

Can we use either PayPal or Authorize.Net for my project? If not, could you please recommend any reliable payment gateway ($US for payment, and gateway located in US please) for that matter?

Answer 1

I found a solution. PayPal calls ProcessReferencePayment.

At first, I need to charge the credit card using DoDirectPayment, and store the successful transaction number.

After that, I just call DoReferenceTransaction along with OrderTotal and ReferenceID (the previous transaction number).

DoReferenceTransactionRequestDetailsType

DoReferenceTransactionReq