Remote API - creating proforma invoice
the current API doesn't allow to create proforma invoice. Correct me if I'm wrong but using billing_invoice_add() function you can only create invoice - there is no option for $override_params variable. You can then change the type using billing_invoice_update() function. But in order to finalize the invoice you need to use the billing_invoice_finalize() function which only allows to assign $invoice_id variable for refund and invoice types.
Is there any solution?