I'd need to know if it's possible to import invoice data from legacy system to Zuora.
The business case is that after the Zuora go-live, and adjustment may be required to an invoice issued in the legacy system.
A debit/credit memo can be issued without reference to any invoice in Zuora, but the business doesn't want to issue a debit/credit memo to a customer without any reference to the invoice that the credit/debit memo is adjusting.
Re: Invoice migration
We've done many migrations from legacy systems. This is how we mange posted invoices from legacy systems.
We created a one-time non taxable product and we named it "Open Balance". Then for customers that have an unpaid invoice in the legacy system, in zuora we create a subscription with the Open Balance charge. The amount of the charge is the total amount of the legacy invoice, tax inclusive. Then an inoice is generated using the legacy Invoice Date and Payment Terms.
The invoice that's generated in Zuora is a placeholder for payment the customer to pay. We typically do not send the zuora invoice to the customer since it would have a different invoice number.
The subscription is usually a 1 month term length with 0 month renewal term. we cancel the subscription once the invoice is posted.
Some other things that we do: We reference the Legacy Invoice Number in the Suscription Name, if the legacy invoice number is 12345678, then the subscripton Name is hardcoded as OB-12345678. We also created a custom invoice field "Legacy Invoice Number". once the Zuora invoice is posted, we mass update the field with the coresponding number for reference.
Does this help? Let me know if you have any questions.