The machine has a hydraulic chuck and the drawtube moves to open and close the chuck. If you attach a stop to the end of the drawtube behind the hydraulic cylinder it will move, it will not be a dead center.
Depending on how long and what diameter your parts are it is possible to rig stops.
If your parts are small and short you can remove the inner liner piece at the front of the chuck; this is held in with three little socket head screws. Make a longer one and mount your stops in this.
Another way if your parts are long is to fabricate a bracket at the back of the machine with a bearing to support a stop on a shaft inside the drawtube. This stop rotates with the spindle but because it is held in its own fixed bearing it does not move with the draw tube.
An open mind is a virtue...so long as all the common sense has not leaked out.