How can I add Auto-Mute Mode to alsamixer?

Question

I have a laptop which has a standard Realtek 5.1 surround soundcard installed along with an Nvida HDMI one. The issue I have is that the sound does not mute when headphones are plugged in and I believe it has something to do with the fact that Auto-Mute mode is not available via alsamixer, nor it is present when I produce an Alsactl output. It should look something like this:

control.## {
        iface MIXER
        name 'Auto-Mute Mode'
        value Line-Out+Speaker
        comment {
            access 'read write'
            type ENUMERATED
            count 1
            item.0 Disabled
            item.1 'Speaker Only'
            item.2 Line-Out+Speaker
        }
    }

But its just not there. My question is how does Alsactl get its information to setup the controls and is it possible to override the controls and add the 'Auto-Mute' mode manually?