Generic Solution to Provide Ariba Punchout Authentication


I am currently trying to figure out the following solution based on Ariba Punchout with webMethods Aribe Supplier OnRamp:
before the punchout happens, the buyer will be authenticated by the supplier site in order to gain access to the catalog system.

Since this requirement is to all buyers who want to access the catalog, I would think of setting up an authentication/authorization server to handle this as the entrance to the ecommerce site. Or maybe for the time being, in the request I can embed the user name and password to get authenticated along the process.

I do need a second opinion from some experts here on this …
Thanks a lot…