Setting up sound on EP45-UD3??? Problem with front earphones.

The EP45-UD3 motherboard uses the Realtek Azalia audio chip.
I have downloaded and installed the latest Audio drivers from the
Gigabyte Web site. I am using Creative 2.1 speakers (I've forgotten what
type, but they sound nice).

I have plugged the speakers into the green plug hole at the back. The
speakers work fine. My problem is that when I plug in headphones, they
don't work!

I then go into the "Realtek HD Audio Manager". The only way I can get
the headphones to work is to tick "Disable front panel jack detection".
That seems counter intuitive to me. Anyway, both headphones and Speakers
are working. If I click in "Mute the rear output device, when a front
headphone plugged in." still both front and back are playing!

Does anyone have an idea what I am doing wrong?

What I want is for the headphones to work when plugged in, and the rear
speakers to mute.

cheers
Gorby