Comment 87 for bug 141445

@ Rex
I made a (very ugly) hack to do just that.
What i did was to create a file that represents what (keys) should be inputed to alsamixer and then using a script to redirect that to alsamixer. Both files are attached below.
Then, I ran the script in a terminal at startup. To do that, go to system preferences -> startup applications, add a new startup application with the command "gnome-terminal -e ./alsaconf" (or where you extracted the files). Save and log out/in and rejoice the automatic change (everything is done in the background so you don't have any terminals popping up).

Oh yeah, this works on my VGN-FW140E, but I can't guarantee that it will work on anything else.