Getting the output of Modul8 direct into Millumin is very easy :

1. Launch Modul8 and be sure that the output is correctly set up.
   The size of my output is 1280x480, so here is my configuration :
   
   
2. In Modul8, create a layer and assign a media to it.
   
3. Still in Modul8, set the output in Syphon mode (shortcut : ⌘+Y).
   
4. Launch Millumin and change the resolution to 1280x480.
   
5. From the menubar, click on "Layer" -> "New syphon Layer".
   
   
6. And here is the result :
   
7. By default, the background of the Syphon input is transparent :