`install-amd64-minimal-20141204.iso` asks for a keyboard layout to select at start which is quite helpful, i.e. the function should be available in `install-x86-minimal-20141209.iso` as well or the introduction should contain a hint how to setup the keyboard layout.
It's possible that specific release had a bug and dropped it out. The boot option that controls whether the layout prompt appears is 'dokeymap' and it's included in current ISO's. Please re-open if you're still affected on current releases.