How does Ship and Debit works without Back to Back ordered Items?

Summary: How does Ship and Debit works without Back to Back ordered Items?

Content (please ensure you mask any confidential information): How does Ship and Debit work without Back to Back-ordered Items? When we create a Ship and Debit program, we have to add both the customer and supplier to the program. When the sales order is created for Back to back-enabled items, it creates a PO with the supplier, and that is how the system defines the rebate for the supplier. But how does this work for non-back-to-back items where the sales order is created and then it is shipped from local inventory and not through a PO? How to trace back the supplier of the goods which is shipped