Hi Sireesha,
If you are using stock determination group and system picks the material from that storage location, backflush will also have from the same storage location.
My question is why to backflush from a storage location where the stock is not planned? If you are using 0002 for planning, I assume stock receipt will be there. As well logically issue should be from there itself.
Backflush you can maintain in different places but stock will be consumed from the issue storage location.
Please refer the document if it helps.
http://scn.sap.com/community/erp/manufacturing-pp/blog/2013/12/30/backflush-and-its-priority-in-use
I feel you have to change the storage location manually.
Regards,
Krishnendu.