Search for a nodal slide and that should do the trick for you. You can spend anywhere from $20-$200 depending on your budget. Just clamp the bottom rail of the nodal slide to the clamp on the gimbal and then your camera to the clamp on the nodal slide. It also has the benefit of still being able to balance your camera on the gimbal. I use a Kirk macro slider for this same function, but only because I already had the slider.
