Help with setup

[Metaphor]

Ok, so I recently ordered my A40's and I can't wait for them.
But, I don't know if this is a problem or not, but, I'm pretty sure on one of the setup videos I watched, you need to plug something into the USB drive on the back of the xbox, does the ones on the front of the xbox work for this cord? And, does an optical cable conflict with the HDMI cable?

[PreFLecT]

A usb port is a usb port not trying to be dumb here but isnt that common sense(this cords for charging it BTW)
Also you can use either of these to use HDMI With optical id recommand 2nd one
http://www.chadledford.com/?p=50
http://www.xbox.com/en-US/hardware/x/xbox360hdmiavcable/

[AllTimeMitch]

Just like above.

The USB Cable for the MixAMP when used on the Xbox 360 is only to power the MixAMP. It can be plugged in any of the three USB Ports of the Xbox 360.

The Optical Cable cannot be used directly with the HDMI Port on the Xbox 360. You will need to purchase a cheap adapter from any good retail stores which will let you use HDMI and Optical on the Xbox 360. You can purchase these together from Amazon UK or Amazon.com. Once connected it will push Stereo Sound 2.1 to your HDTV through HDMI and 5.1Surround Sound through Optical at the same time, so you will have to turn your TV down to 0 or mute it.

Amazon.co.uk (http://www.amazon.co.uk/Xbox-360-HDMI-Cable/dp/B000VUVCK6/ref=sr_1_1?ie=UTF8&s=videogames&qid=1260889355&sr=8-1)
Amazon.com (http://www.amazon.com/Xbox-360-HDMI-AV-Cable/dp/B000UODATY/ref=sr_1_1?ie=UTF8&s=videogames&qid=1260889436&sr=8-1)

When connected on the Xbox 360;
Goto My Xbox Channel (Where the disc and Gamercard is) > System Settings > Console Settings > Audio Settings and Select Dolby Digital 5.1. Don't select the "With WMA Pro"