>> think we did talked about this before
definitely
your subwoofer is not connected via a separate connection (located on your card)
in order to use a separate center channel you need to connect to the 'center/lfe' connector of your card
so, if you wish to use 5.1 speaker set, you need to use all the -three- jacks of your card (front,rear,center+lfe)
choose '5.1 direct path' in the surrounder plugin
if your subwoofer is connected to the 'front' speakers, uncheck 'use subwoofer output' in the 'surrounder'
/E