Thiryniner,
I've got it!! I spent about 5 hours on it, today, and some time yesterday, but I am looking at the lock with removed tumbler next to my computer.
You were right that it has to be turned counter-clockwise. It goes about 1/8 of a turn beyond open while, at the same time, pulling back on the bottom of the latching bar that sits on the rear of the assembly. Then everything just comes apart.
I think I probably had some gunk in the mechanism, and that was interfering with the picking process.
In any event, I hope that I have not caused you too much extra effort, but certainly to appreciate whatever you did...and you did give me a good portion of the clue to the puzzle.
Now, I have to see if I can cut the key...???
Many thanks,
Gary
