Smuj,
It required special pallets with built up sides so you could (a) lock the pallets into the side guidance and (b) fork them out of the way after offloading. The J did an exercise in the boonies of Louisiana in 05 which involved tac offloads. They borrowed the special pallets from the USAF and we sent the nsn and specs back to UK, for the expense versus potential usage deemed to be a non starter, shame as it was fun to watch.