The Unity DS-1 ReWire extension needs to be placed in your Extensions folder for ReWire applications like Cubase or Logic to recognize the ReWire audio outputs of the Unity DS-1. You will also need to select 'Plug-in' as the audio IO type in the Unity DS-1 control panel.
Now, when you next launch Cubase or Logic, you will be able to see the outputs of the Unity DS-1 as ReWire audio outputs.