I would recommend NOT trading those IOUs. I’ve noticed that it’s highly speculative buying, and they appear to be playing chicken - who can ride the rising price and pull out right before it dives? And dives it always does, as soon as the IOUs are converted to tokens, and all the gamblers sell off.
It’s irritating actually - I think it really distorts the actual price later. It give the impression of sudden wealth - that vanishes as soon as the actual supporters - us - can join. It creates a depressed vibe around the coin later. If instead it was listed along with everybody else, I bet the price would do much better overall.
But, if you really want to do it, the idea is that you put up cash toward them, not actual Tezos (if that were possible). Hitbtc has created a pool of objects they just call Tezos - that will be converted to actual tokens on release day. They make money off the wild speclation