DISSREGARD ALL THIS LOL
i just under stand what you meant in question and my answer doesnt help lol :p :p
yer i think this keeps it even if you close it down im not quite sure lol
anyway you click the little button with the arrow pointing "into" the boxy thing to temp save into maya and when you next load the render view it will still be there.
Sorry for the rushed answer but im on my way out hope you understand lol
"While I recognize the necessity for a basis of observed reality - true art lies in a reality that is felt"