Get a longer half inch brass or SS pipe nipple, and then friction fit it through the hole. A coupling on the inside and the valve on the out side along with some washers and some o-rings and your set. The friction fit part is a recommendation, I have always had issues with this point as a leak area. Just a tiny one, but a PITA none the less. S.
Primary: American Wheat
Secondary: Phils Pils Clone