hello, i'm no expert but i do know the problem you are talking about and asked a professor of mine about it, his reply was that those modes(roto-wire/shade) are more for being used as guides when drawing off referance material, so there would be no point in being able to zoom since the camera will only see the 3d object in front of it. he said there was no way you could zoom in to it as far as he knew, i myself don't think it's possible because me and my buddies have tried and failed. hope i was of some help.