http://service.sap.com/rds-aribap2p
Hello All,
First of all, apologies since its almost a year later, that I am responding to the ticket. But as it goes with a very old saying, " Better late than never ", it might help others with the same question.
There is an RDS package that guides experts on the integration of Ariba Buyer realms with SAP ERP, and it supports various connectivity options, say like over PI, or ITK or just send the master data via a Direct connectivity, etc.
You can find more information in the link above. The page also has contacts, if you need more information on the topic.