Conformation control key

Hi All,

I have configured a new conformation control key Y001 by copying 0001. When I use this in the PO it makes it mandatory to create an inbound delivery before GR. But after creation of inbound delivery in VL31N it still allows GR against PO and does not make it mandatory to post GR ONLY against the inbound delivery.

Is there a way to make it mandatory to post GR ONLY against inbound delivery and not against PO.

Regards,

V S