I tested it now, and what I think I did now was choose between:
Either making a smooth transition beetween the frames, but making it blurry,
Or,
Not making a transition between the frames, but with a more (not really sure what word to use here, I’m norwegian :P) choppy result.
But
What I want to do, is to make Vegas create new, artificial frames, in order to make a smoother slow motion, I think it’s called iterpolating frames.