My first attempt was two separate molex lines.  My second attempt was off the pci express (3x 12v lines there).  I then also tried two molex plus the 3 12v pci express lines which should provide more than enough amperage.  Like I said before, the psu powers up fine when the blade isn't connected, which is how I can confirm 12V across the green power plug.  I don't have anything else drawing power and it's a 450+ W PSU.  I've swapped out the PSU and had the same trouble with my "used" PSU.