This could be a senior moment, but aren't the pins on the mobo? I have an Audigy 2 and have disabled he on board sound chip and have the front conecions on my Antec case connected to the mobo jack, as I recall.
edit: Yes, of course, you are right. Dumb me!
My Asus mobo has a plug for the Sonata front jacks, which uses the 10 pin plug. I have the onboard sound chip disabled, so, of course I can't use the front jacks.