From the FAQs on the Antec site click here - is this it?
My Fusion has a 4-pin Molex power connector with blue and white wiring. What's that?
That is the front Power LED connector. Please connect it if you wish the blue LED indicator to light when the power is on. And please note that instruction 3 of "Connecting the Power and LED" on page 2 of the Fusion manual has been superseded.