I scoured the internet for hours looking for someone to tell me how they rigged the sheathes to their body. So! What I did was hot glue adhesive velcro onto my pants OVER the belts used to keep the maneuver gear in place. I then hot glued adhesive velcro on the sheathes. This way belts AND velcro hold the sheathes up, making it super easy to move around.
I hope that helps!