ah you wanted to run them at the same time? i just thought you wanted to use them independently...
with usb you cant coz it automaticaly mutes any other output. but if you were using 35mm jacks then you can turn off mute speakers when front jack is pluged it. sorry i got confused...
you can only select 1 output at a time... meaning that if you have realtech. you can use the audio panel to turn it on and all the jacks will be live audio so you can plug in multiple devices and get output from them all. but usb will use a different sound engine thus muting the realtech...
the problem lies with windows itself it only allows 1 output device at a time to be use. but like i said if you have a sound card that has more than 2 35mm jacks you...