iSupplier - Create Invoice without PO

We are on Oracle EBS 12.2.9 and are working on setting up iSupplier. I have a question for the iSupplier / Payables Invoice experts.

My question is regarding how to apply Distributions to the Invoice, especially for Invoices that are created without a PO.

I have turned on Invoice Approvals and have the boxes checked for (1) Require Validation Before Approval and also checked for (2) Require Accounting Before Approval.

However, when I create an Invoice without PO it initiates approval right away. My question is, how can we get the Distributions applied if the Approval is initiated immediately upon the supplier creating and submitting the invoice from the iSupplier Portal?