Could be ( if I understand you correctly ) you have your camera set to front view, hence your grid being behind the image plain.the problem is that the grid is behind the imageplane. so i can not see the grid.
I have never ever ( to my knowledge ) been able to move or seen anyone move a image plain behind the grid display in Top, Front, and Side views. Even the online tuts and books that I have read have never shown that kind of a feature.normaly in maya when you have imageplane in all views , in front view-topview-sideview the image plane should be behind the grid not in the infront of grid only in perspective view is different, but with my maya i see the imageplane in top-side-front view infront of the grid.