Also, once you've created your MIDI controllers, make a copy of your Jupiter 8V preferences (in User/Library/Preferences) and save them somewhere else on your HD.
A couple of times I've opened up Jupiter 8V only to find that it had 'lost' all my MIDI controller assignments, which is very painful since it takes quite a bit of time assigning al those controllers.
Now I just copy my saved preferences to the Preferences folder if this happens.