For those following this saga, I am now working on the valve. I have replaced all the bad o rings, but I have no idea what I replace on the regulator valve pin assembly.

http://www.tunamart.com/index.php?c=39&p=115

Where that white part is, on my gun there are three different discs, seemingly of different materials. They are all gummy and ruined.

Is there a part I can pick up so I don't have to buy the whole thing? Seems kind of wasteful if I can't throw something on there.