Ok, after doing a few minutes of research, something I probably should have done at the beginning. I figured out what I bought, why it works and what certain terms mean in the world of latches.

The correct locking handle is the Southco 92-41-511 . This is the clockwise rotating, .63-.75 grip range handle.

I got mine from Austin Hardware . It cost me $27 + $11 shipping. I got in in about 3 weeks from the time of ordering (it was backordered). The installation instruction I posted above are accurate for this handle.

Grip Range: http://www.southco.com/resources/literature/2-1-1.en.pdf This PDF file shows what the grip range means. Witht he Xterra latch this is not important as you use the spacer and nut that comes on the factory handle.

Clockwise -vs- Counter Clockwise: This is the direction to latch. Since the X's handle counter clockwise to open and clockwise to close, you want a clockwise handle.

Links used in this post:
http://www.southco.com/product/part.aspx?pid=11917
http://www.southco.com/glossary.aspx#G
http://www.southco.com/resources/literature/2-1-1.en.pdf
http://www.austinhardware.com/product.as...PRQXQ3L4EA7712D

That should about cover it.