Hello,
I have not had the privelage of picking that lock, but I may be able to offer you some pointers.
The reason that you are most likely not able to set the other pins in your lock is because of the binding order as pickin touched lightely upon. Is what you are probably doing is over torquing the lock (by using too much tension on the tension wrench) and are then picking a pin that is just barely binding while not actually picking the MOST binding pin.
For example, say that the picking order for your particular lock is 34215. (Meaning pin 3 (from the front) is the first most binding pin, then pin 4, etc) Say that you then apply too much tension and do not pick pin 3 first but pick say pin 2, then you move onto 4, and then maybe even pin 1. This entire time, the plug has been rotating the tiniest amount each time you have picked a pin. When you try and come back to pin 3 which should have been the first picked pin, the plug needs to 'unrotate' which causes the other pins that you have already set to fall back down.
Sorry if this is a bit confusing, and I hope this makes sense. This is one of those locks that being able to identify the binding pin really helps.
Good luck and keep us up to date with your progress,
Cheers,
Treeson