Thyrm switchback, help?

I just received a switchback and I am trying to install it on a p1r peacekeeper, I am having trouble. with the switchback installed the light will not activate. From what I have seen it is compatible, am I doing something wrong? I tried it with and without the extra o ring. I watched the youtube install video and it shows it works with the clicky switch models.
Anyone else have the same issues? Suggestions?

Here are some photos...
https://drive.google.com/folderview?id=0B3Z6oG2et7q-VkFmaUNfMjNHQUE

If anyone interested or having problems, I figured it out. I had to sand down the bottom of the switchback. The lip on the switchback, that goes in the groove in between the body and cap, was a few millimeters to wide. The cap couldn't tighten down enough. I put a piece of sand paper on the table towards the edge and I put the switchback flat on the sand paper with the clip off the edge. Putting even pressure I moved it back and forth on the paper. It took about ten minutes total, basically sanding and testing.

I don't know if this was just a one time thing and I got a bad one. Maybe I just got one out of spec due to the manufacturing process. Because it seems they are supposed to fit, and are designed primarily for surefire lights.