Third Party integration

This may be the wrong place but We have a third pary application that is reading invoice submissions for both purchase order and on purchase order (Basware). We are having difficulty getting the non Ariba purchase order invoices to post to the s4hanna system without manual intervention in Basware to add information. How difficult would it be to set up a tranfer file from Baswar to SAP that would go to the purchase order match the material/ quantity/ unit price/ or total line amount to do a line match and post the invoice details quantity/value to the purchase order?