@manderegg - If I understood it correctly, you have a customer that uses Coupa. They will send you POs that need to be imported as sales orders into your NetSuite account. When you invoice the POs, you need to send the invoice back to the customer’s Coupa account. Is it correct?
If this is correct, the POs will be transmitted to you in CXML format via POST requests. You will have to process this CXML file and create the sales order in NetSuite.
Then when the SO is invoices, you will have to convert the invoice into the CXML format and submit it to the customer’s account.
CXML is the only option to receive POs or create invoices in customer’s Coupa account.
We have done this integration before with a custom Nodejs server and NetSuite scripts.
1. Coupa sends POs to the Node sever > the server translates CXML to JSON > the server sends the PO to a restlet script in NetSuite > the restlet script creates the Sales Order
2. Invoice is created in NetSuite > Script deployed to the invoice sends it to the node server > node server creates the CXML and submits it to Coupa