I’m getting conflicting information. One set of recommendations (mostly forums) says I should disable the "synchronize with control panel" tickbox, set the control panel to 5.1, then the creative console to headphone mode. That way, I’m able to listen to virtual 5.1 sound from 2 channels.
 
The other set of instructions from here http://www.creative.com/products/soundblaster/howto/show_flash.asp?filename=GameInter_Headphone.swf and here [...]