This is a hot swappable supply that plugs into a power distribution board. That board breaks it out into standard ATX connectors, so if you can get hold of it your problem is solved. Failing that, I can't find a pinout anywhere so theres no safe way to proceed. You could plug it in, and look for pins which are +5V relative to the PSU chassis. One of those pins should be the equivalent of the ATX green wire and, when shorted to the chassis, should power up the supply at which point you can meter for the 12V and GND pins. But this is assuming that this is essentially a repackaged ATX supply, so it may not work that way at all. Short those pins through a small value resistor because the one that isn't the power on pin is the +5V standby pin and you don't want to draw too much current through that.
