Hmmm....I'd make it into a sleepover party at first. Make a big deal about their having there own room and own beds and put a palette or a mattress on the floor between their beds. Then read stories, tuck them in and say goodnight. Lie there until they crash if they need you in the room. Just a suggestion.
Ultimately you have to follow your heart on what to do. It might take a few days but you'll know what they need and if now is the right time or not.
Thanks! I am a part of the twins discussion group on Twinsmagazine.com, too, but I really like the empasis on natural family living on this forum. My husband is a Naturopath, and I am working toward a certification in Childbirth Education through ALACE(focusing on natural and home birth). In am also an aspiring Doula, but I am a little too busy right now.