John,
A word of caution. The fill valve on my broke. Below are three pics of the fill valve parts.
First pic are the individual parts. starting at the left is the part that screws in and holds the whole fill valve. Next is the tube that moves to let the gas in from the fill bottle. Next is the spring that pushes the fill tube closed once you remove the fill bottle. The last part on the right is a cup that holds the spring and fill tube in the part that screws the whole assembly into the tank.

The point of the mechanical pencil is pointing to the crack in the side of the threaded part.

Here's a close up view of the threaded part that is cracked. The cup part is pushed into it.

This the reason I think that it only worked once. The threaded part could have been craked to begin with not sealing the tank tight. The gas would slowly leak out.
Just before I cut the whole thing apart I wanted to try one more time to fill it. When I pushed the fill bottle down on the valve it gave way and I was sprayed with the butane. I believe this fill valve to be a danger. I won't use it for anything else.
This has lead me to two conclusions as to why mine didn't work. It was either a deffective fill valve or a piece of dirt in the jet or both.
I'll take some pictures and a write up of what i did to change it over to use a propane tank in the next couple of days.
Regards,
Bernd