John,
Not sure it would work on a steampro. Mine hangs on the back handle of my Enforcer and the vac hose runs from the bottom of the booster to the outlet of the vac motors. From memory I don't recall a dedicated exhaust outlet on a steampro. You would need to have a barb fitting attached to the exhaust of the second vacuum for the booster. Also you would need a mounting point for the booster it weighs around 10kgs.
If you can get it to work its definitely worth it as it will improve performance.
joe