Dear Snowscuba,
Sorry for the mispost above.
You can buy either a 10 Bar, Inon or Ultralite YS adaptor. Just take out the o-ring and push the ball end into the narrow end of the loc-line segment. It's a very tight fit and will take considerable effort to pop it in. I added a couple of zip ties to connect the loc-line segment to the YS adaptor for extra security (just in case it comes off underwater).
To mount the loc-line segments to the tray, you need to get the loc-line fixed mount. It comes with a hole in the middle so all you need to do is buy a stainless steel bolt, nut and a couple of washers. Drill the appropriate sized hole on the tray (a good piece of scrap aluminum should do) and bolt on the fixed mount to the tray. All you need to do now is attach the segments to fixed mount and the other end with the YS adaptor and you're good to go.
BTW, you need to put another hole on the tray so you can attach the camera via the tripod socket. You'll need to find an appropriate mounting screw as well.
I've been using this set-up for a few months now and have never had any problems. The YS adaptor stays connected and has never come off, even in heavy current.
Hope this helps!