Don't do it.
Scuba tanks are very strong. Valves, however, aren't. They are made of brass and chrome plated. It doesn't take much to damage or worse break the valve.
You don't want a loaded tank taking off inside your jump should the valve get loose.
Master Scuba Diver Trainer
Dive Shop Manager
Texas Hunting Rig - 89 YJ/CJ Hardtop with Safari Racks, 4.2 L w/ Weber 34, 31x10.5 Pro Comp Extreme Mud Terrains on Black Pro Comp rims, sound bar, seating for 8, 4 receiver hitches, 4 KC Daylighters, and 2 cupholders. Rancho 9000 shocks with in-cab remote switch.