Hi Amol
Unfortunately, that is still not possible even on PO 7.5. Check the conversation between Shabarish and Alex in the comments of the following blog.
What’s new in SAP Process Orchestration 7.5 SP00
It is only possible to provision OData services from SAP backends using Integration Gateway on PO and Gateway on the backend. Non-SAP backends are not possible.
Regards
Eng Swee