New Speakers for the A7N8X/dx, Need a bit of help!

I just received a set of Logitech Z640 digital SS speakers for my computer system.
There are 3 coax male plugs to be plugged into the sound out from the nF2 mobo.
I have read the manual, and the pamplet for the speakers. The instructions just state to match the colors from the cable to the sound out on the mobo.
The only problem is the colors do not match. Only one the green, which is the main speaker out for most speaker systems. I have that one right.
I have the front and rear left and right speakers to the two outlets next to the S/PDIF outlet.
This is where the Asus manual says to attach the left and right f & r . They do sound great, this way.
I had to expierment for a couple of hours, with the wife in the chair I usually sit in. We came up with a combination that really sounds great. The only voluce controls are the main volume control which turns up and down all the speakers. Then a volume control for the rear speakers.
I have the rear speakers set to where we cannot tell where the sound is coming from. R or F then the center speaker has it's own controles.
I have it set to where you can hear it but the volume is about the same as the front L & R speakers.
I am used to a control panel that allows the volume to be adjusted on all SS speakers. This one only have a control on the whole system, the rear speakers and the center speaker. That is all the control I have.

The bass has it's own volume control on the back of the speaker. The bass in this system is super great.
A 12"x12x wooden box with a large woofer designed for maximum output of low tones. Works great.
My question is do any of you guys have any Logitech speakers and how do you have them attached to the mobo outlets?