Even saving selected intro/endings to disc is apparently somewhat limited. For instance, say you want to create two Registrations for two songs using the same style, but different intros and endings for each. No Can Do. At least I haven't been able to. Whatever intro/ending you save for the first song will forever be the default on any song using that particular style.
Maybe saving the two songs to different discs would be the solution...but changing discs or punching in intro/endings takes about the same time.
Eddie