beep, usb devices e.g. soundcards or headphones are classed as an audio device (will generate an entry in device manager) .. you could use WDM if thats what you mean..but it's just easier to route the 1010 to a heaphone out , which you can do / it's an option on the control panel next to the clock, buttom right of the screeen.. is with the 1010LT anyway
to the OP, just send one outputs to output "main" and use that as your headphone and you can control that within sonar volume wise also.
http://www.computercablei...-Female-Cwholesale.jpg should do the trick , just put it on 1 pair of the phono outs, plug ya headphones into that or an extension .. hopefully it has enough power to do that.
how mine was setup , I have a pair of logitech speakers with a sub for testing... that has a headphone socket on that, which I use sometimes.