Enterprise Services and PI
I am looking for some white papers / blogs on calling SAP Enterprise Services via PI. I would also like to get sdome idea of the following points:
1) A typical scenario using Enterprise Services
2) Is it possible to extend Enterprise Services as one might a BAPI, in order to enhance it specifically for a customer?
3) What is the performance like compared to posting IDocs via PI?
4) Is it better to call Enterprise Services via XI, or directly into the ERP system?