RE: Sweetest Charger Ever!
It's REALLY REALLY easy. Plug the power supply in, and then short the green wire in the long plug to any black wire in the long plug. To test with, it's fine to use a paper clip stuck into the plug to short these. That tricks the PSU into powering up. Not all PSU's will work for this, so try all three and see which ones power up when you short those two wires. Of the ones that do power on, use the one with the highest rating on the 12v+ rail. This info should be printed on a sticker on the outside of the PSU.
Once the thing is powered on, all you need to do is plug your charger to any yellow (12v+) and black (ground) wires. This will power your charger. If (only if!) you have problems maintaining 12v on the PSU while charging, you can add some resistors or a fan on a red (5v+) and black (ground) wire.
J.