Just find a brass fitting with the same thread pitch and diameter and you should be set. Only catch is that you'll have to unscrew and remove the actual schraeder valve "guts" out of there so the fuel can pass through (be careful though as the fuel line will be pressurized even with the car off so relieve the pressure first!). I think you can buy a tool for doing this from a bicycle shop. The Tire guys use it to deflate you tires in a hurry when you go and get tires etc.
