Hi Ajeesh,
Since today is a holiday I am not before the systems and hence tomorrow I can suggest you regarding the possible values to be filled but I don't remember facing such issues while activating WTIN. Anyway I can comment on that tomorrow only.
Please have a look at my reply in the below link. It contains almost all the OSS Notes related to FIWTIN_QRETURNS. Let me know which are the Notes you have already implemented.
https://scn.sap.com/thread/605664
Thanks & Regards
Ramesh