PeopleSoft 9.2 Billing integrations to Coupa/Ariba

our clients are requesting that we directly integrate our billing processes to their Coupa, Ariba, etc systems along with enriching the data with additional information. We are examining 3 different solutions

1) generate cXML files and invoice PDF and send and load directly to Coupa/Ariba etc., then log in and manually enrich the data

2) Create a tool within PeopleSoft to capture the billing information. Enrich the data and then integrate to the tool.

3) Create an external tool to capture the PeopleSoft data, enrich the data and send to the clients tool of choice.