eKey binding compatible with OpenHab 2?

I would try to install and test the ekey binding, but it seems, the binding doesn’t come with openhab-offline.
As apt-get install openhab-addon-binding-ekey also doesn’t seem to find the binding, I’m a bit lost here on how to add the binding to my openHAB2.

Do I have to add some source to apt.lists or am I missing something other?

Thanks,
Thomas.