i dont have a ms18, nor am i in australia, BUT i can do some cad for you (and print it too if youd like)
iirc the ms18 has a tripod mount, if not you could use a clamp style mount. pressing both buttons would be a little more difficult but still doable.
if you have any drawings/sketches of how youd like this to work lmk if youre interested. the easiest way to do this is to remove each individual lights button and wire it to one on the new handle