Not able to identify fields in my inbox app to extend the list section

Dear All

Please could you help me fix an issue .

We have installed the My Inbox app and need to map the fields from Master section to the left side on the list section .

I understand that Odata service being used is /IWPGW/TASKPROCESSING  and when I see in /IWFND/MAINT_SERVICE I do see it there

And when I run the SAP Gateway client from the Tcode /IWPGW/TASKPROCESSING I see terms like App collection and it

looks very difficult to identify from where this data on the right side is getting populated and how to map to the left side

Could some one please advise its a bit urgent as I have been researching for a while but could not find any solution .

I have referred to the link as below but no luck

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/00bba603-3bfc-3010-c4b9-973ee395e9c8?QuickLink=index&overridelayout=true&58652073497247

Can see the Odata below :

I am trying to extend this now but I do not see it in SEGW :

Regards

Vinita