For me no special key was working out of the box. Which desktop / window manager are you using? Maybe there are some predefined acpi roules coming with those.
That's really strange, all special keys worked for me out of the box, except F11 and F12, but they aren't mapped(as far as I know, there is already a bug report on this). F1-F4 i remapped with keyboard shortcuts.
I'm using XFCE 4.12.
I think using xfce brings some preconfigured acpid rules for the t470 special keys. Im using i3 4.14.1 where those rules are missing and had to be added manually.
Yeah that could be possible. So in this case it would be awesome to create a section for the special key commands. But does this apply only for the t470?