
"We are working with a supplier who has a well established web shop. Our buyers are used to purchasing directly from the website. Right now we are trying to perform all purchasing via SAP Ariba. What we would like is for our employees to continue shopping on the website of the supplier, while we track the spend in the SAP Ariba procurement application."

"What you need is to use a PunchOut catalog setup. PunchOut catalogs (cXML) are live, interactive catalogs that are hosted on the supplier’s website instead of being uploaded to SAP Ariba Procurement solutions.
In the Catalog UI, your buyers will see a link to a supplier’s external website. Users click a "Buy from Supplier" button, and punch out of the Catalog interface to the Home Page of the supplier’s site."
Note
Because PunchOut catalogs use the supplier’s website there is more complexity in configuration, and suppliers must have the infrastructure and tools necessary for PunchOut transactions.