Manual mapping shouldn't be required for most current desktop environments. GNOME and KDE certainly do, and I think Unity does as well. If your desktop environment doesn't map those keys by default, please file a bug against it.
It's great that Linux makes it possible to manually fix such things, but it's even better when they work out of the box.
It's great that Linux makes it possible to manually fix such things, but it's even better when they work out of the box.