Any 5th wheel hitch operate exactly like a semi 5th wheel?

Seems odd that you have trouble with yours. I've had mine for nearly 8 years and only recently found out about pinning the release arm back. I pull the arm back and back the truck into the pin, the release arm flips back and the trailer is locked. I've never not had that happen. True, sometimes the release arm won't unlatch, but that is only when there is some tension on the hitch. Moving the truck a little to unload the hitch is all it takes. I've never pinned the arm back while unhitching.

I love my B&W hitch. :)