I can't see how a water jacket could be added to the stove.. a water jacket is on the outside of a firebox, in essence making it a boiler.. I can't see it working very well, and it would ruin most of the heating ability of the stove,, as a stove..
If you mean an internal water 'coil' or loop for collecting heat and heating domestic hot water,, then if this is a hopper fed stove, is there room around the hopper??? I'm not sure,
I'd call Hitzer directly and ask them..