Ariba Integration with SAP PI 7.3

Dear Experts,

I am working on Ariba integration. This is new experience for me. i have searched SCN.  I found useful blog

http://scn.sap.com/community/pi-and-soa-middleware/blog/2013/02/26/how-to-connect-sap-to-the-ariba-sn-using-netweaver-p-integrationorchestration

I have few questions in my mind

1) Can we use Proxies from ECC end.  (I read in comments that ariba supports only idoc based communication)

2) any step by step scenario documents available?

Thanks & Reagrds,

Pavan