I'm using xfce4 since years also on my laptops and the volume keys (including mute) worked just fine. Since the upgrade to version 4.6.0 they don't work anymore. I've checked out the events produced by those keys (xev) on three different laptops and all of them created XF86audio... events, which was interpreted by some multimedia applications running on top of xfce4 (for example gmplayer). Unfortunately the new versions of the xfce4-mixer seems not to be able to interpret those events. Other changes since 4.6.0. are forcing the user to open the mixer application to change volume (it was previously possible by clicking on the applet button) or mute it, it is quite annoying. I'm really considering to change to gnome (volume setting works just fine). In my opinion the changes of the mixer applet (compared to 4.4) are everything but not positive.
Hello, This feature is available in xfce4-volumed, for the record.
It works for me now after upgrade to 4.10 (wasn't working with 4.8). (This is even without xfce4-volumed!) If you're still using xfce, can you report if it's working for you now?
Fixed in 117ff721b989bcf8cd8e0fbeaa692c14c1ecf5ef.
But the changes prevent now adding many audio mixer's on panel: https://bugzilla.xfce.org/show_bug.cgi?id=10588