Hey dude thanks for your reply, i had another play around with the settings and i found out that it was just the way in which i was hiding the faces. I had to hide the faces, by going Editable poly - selection - polygon - hide. Then i had to deselect Editable poly and go back up to Projection and then hit render. I must of…
You don't have to use push....if it is indeed mental ray your using, simply go into the face sub object mode, select all the faces of the low poly model and click hide faces (not hide object). Click back on your projection modifier and your cage should appear around the now invisible low poly model. Hit bake and your done.