I don't think the valve is necessary. I did notice that most dive lights have a small catalyst in them though. They are small pelets that cause a chemical reaction to take place. I am not sure exactly what happens, but I am sure it is important as all my dive lights have them. They also came with a warning sticker stating if the pelets were ever damaged to replace them promptly. I am sure you can just use some replacements from another light and plop them in your setup.

Nice job by the way! Can you post some additional photos. It is hard to see much in the one photo you have. Some inside views and some explanation on how you did it would be great.