EURkey keyboard layout not showing up [$30]

I'm using Loki 0.4 and I've installed the eurkey keyboard layout (http://eurkey.steffen.bruentjen.eu/) . The layout symbol is already under `/usr/share/X11/xkb/symbols/` and I can use it by applying `setxkbmap eurkey`. The problem is that the layout is not listed under Keyboard Settings and I cannot select it. It's not available under any of the languages and it's not listed as a separate Layout either.

I've tried resetting the xkbmap and rebuilding the rules but it still doesn't appear.

The EURKey layout appears in the list of layouts when configuring the keyboard with `xfce4-keyboard-settings` and I can add it, but those settings are only for xfce. How can I add external layouts to elementary? Is there a seperate UI cache for keyboard-settings that needs to be cleared?