Aspect ratio issue - maya render globals

Hi there, I’ve got a problem with an animation I’m doing, I’ve set up the camera animation on the file with a aspect ratio of 4 - 3 and I really need to get it rendered out at 2.35 - 1, when I change the resolution in the render globals the height is cropped to fit the new aspect ratio. Is there a easy way (or a hard one for that matter) to change the aspect ratio so it adds the extra dimensions to the sides of the 4 - 3 crop ie the height of the file stays the same? If I have a sphere at the top and bottom of the screen in the 4/3 I need it visable in the 2.35/1

Ahh yes change the film fit of the camera.