Nah, Carl, all of the hardwere is already there, that's the beauty of this system. You see, what they do is to rotate the missile to the side, and then they line up the launcher rail with the trailer's rail and they just slide the missile onto the launcher rail from the launchers front, if I'm not mistaken.
I did a quick search and I got some more info for you - the reloader we're talking about is oficially designated PR-11. When the tractor changes to a more modern machine, this designation also changes.
Here's the picture of the actual missile transporter:
Here's one pulled by a more modern ZiL-131
And here's a nice drawing from a Polish site:
This funny outline on the trailer is an optional canvas cover - once I thought it would be cool to model those canvas, but then again it would put the missile out of sight, and it was also almost never used anyhow.
Here's a nice one, showing the start of the reloading process:
Now imagine they rotate the rail 90 degrees and slide the missile backwards on the launcher. Shortly before that the missile would be tanked with compresed air and oxidant (from the large tank in front of the reloader). Please note the stand, the rear reloader wheels are standing on, to make sure they're on the correct spot.
Hope it helps, have a nice day
Paweł
PS. Oh, and that link is soo cool!