New computer front panel wiring question

I purchased a CoolMaster Centurion 5 case from New Egg to build a new
computer. I am using a Gigabyte GA-P32-DS4 motherboard.

There are two wires in the Centurion 5 with separate connectors that
are not labeled. They are white and green and they are twisted
together. It was my guess that they were either supposed to be
connected to the "Message/Power/Sleep Led" as listed on page 30 of the
GA-P35-DS4 manual or that they were supposed to be connected to the
"Power_LED" three prong connector on motherboard.

The manual does not identify any of the front panel connectors though
all but these two wires are labeled on their respective connectors.

Also, the Gigabyte manual states that the connectors should be
installed respecting the pins positive and negative assignments. All
of the Centurion front panel connectors have a white and a colored
wire. Is the white wire negative?

The Gigabyte manual, other than noting on page 23 that there is a
"PWR_LED" header, never describes actually connecting it to anything.

Any thoughts?

TIA