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Well finally I figured it out myself

We have to use DrawFilter and there use resultSet etc and use page property as a parameter.
There seems to be no other simpler way.

If anyone needs any help in ever implementing the same. Pls feel free to ping me nv@nv-enterprises.biz

With Postman and soapui you are hitting the url straight not via a network protocol, thus it giving 200.
What I think  you should check system logs to see whats the error thrown by the rest application. I feel its just an authentication / authorization issue

Feel free to share logs if it doesn't resolve

Thanx to all and esp to Eduard

I used a mix of Eduard's code, docs, EnsLib.PubSubOperation and some of my code

From my BP -  I am calling the PubSubBo with a response of arrays that gives me targets in a string array 

- BP then sends to all targets from a call inside a loop of targets array. The target of which is set dynamically from context of the loop element.