I've opened a new thread on this matter, (http://www.nvnews.net/vbulletin/showthread.php?t=62656
Both kmix and gnome-volume-control show the same options. I've also added some screenshots to the post.
djalma, does your soundcard detect wether the headphones jack is plugged or not? Or, at least, can you set the headphones volume, or toggle speakers mute without muting also the headphones?