Exposing serivces as Odata in PO

Hi, I have read about exposing gateway services via SAP PO as Odata-

http://scn.sap.com/community/process-orchestration/blog/2014/11/26/exposing-gateway-services-from-process-orchestration

http://scn.sap.com/docs/DOC-63974

Exposing Back-End Data as OData Services - Process Orchestration - SAP Library

My question is, Can we expose any service (for an instance a service interface built in PO for a non-sap system) as a odata service directly using PO odata adapter? To explain it in a better way, Let's say I want to build a normal synchronous ODATA to SOAP scenario. The request would come to PO through Odata -> It will be converted to soap structure in PO message mapping-> It will hit the backed soap service -> fetch and return the data back in odata format to the requester.

In brief, My questions are -

1) Is above mentioned scenario possible in PO alone?

2) In order to expose SAP service (for example an RFC) as Odata service, Can't we expose directly via SAP PO alone? Would we always need gateway service enablement in backend SAP system.

Thanks,

Amol