I am familiar with the company and the valves but I think you will have a few problems there surfdoggi, Submarex went into liquidation, I am guessing early 2002 / 2003 somewhere around there anyway.
They never manufactured the valves themselves, they were made under their name in Germany, but I dont know the manufacturer, they also made a regulator which, many said was a copy of the ScubaPro, but I never really saw it around much so I cant imagine they sold many.
Sorry to be the bearer of the bad news, but I think you can toss the valve unless a collector somewhere has spares, or you can adapt parts from another brand - which is not too unusual actually, few valve manufacturers make their own spindles, seats, handwheels etc, usually they just buy these from mass producers somewhere like Sanosub or Finesso in Italy, so internals are usually interchangeable on a lot differant valves.