Where do you locate the mni-DVR?
Quick and easy is just to velcro it to the side. Alternatively there are some guys selling mounts on ebay to allow you to helmet mount the monocular. I have a pouch/cable on my helmet if I need to record out of the monocular.
Search on "hd19 helmet"
I'm confident you would not want a cable long enough to go from your hand to your back or even your chest for that matter.