Don,
The trailer plate is only relevant to the Superglide hitch. For those of us with the Superglide, our coach does not rotate on the kingpin. The entire 5th wheel plate on the hitch rotates, as it rotates it causes the plate to slide back 14" on the way tubes to allow enough clearance between the truck and the coach. The trailer plate has a "pie shape wedge" that fits into the opening of the hitch where the kingpin slides into place. While doing so, it will automatically trip the locking mechanism which wraps a full 140 degrees around the kingpin. To get a better understanding I have linked the 16k Superglide owners manual which shows pictures and offers a better explanation of the process.
http://pullrite.com/pdfs/3300_16K_SG_OwnersManual.pdf See figure 3 on page 4, and figure 4 on page 5. That should give you the best visual example.
Pullrite also makes an adapter for the Superglide. If you do not have a Superglide hitch, you cannot tow a coach with a Superglide mounted trailer plate. Pullrite has come up with a solution to allow a modified coach to be towed by conventional 5th wheel hitches. See the link,
http://pullrite.com/pdfs/3336Conversiondaptor.pdf Right above the word "NOTE" is probably the best picture you will find of the adapter.
If this has throughly confused you, you can see a free video from Pullrite on how the Superglide works.
Go to
www.pullrite.com and click 16K Superglide. On the right side of your screen should be a link for Product video.