PS. I just realized one important fact I'd like to point out because it illustrates to all readers the exact, exact problem. Again, it may not apply in your case, because I don't know your system or your parts, so please just dismiss this if it doesn't apply in your case.

In many DD persons, one part of the self can feel trust and say they trust and believe that "I trust," and the therapist, working only with the porch of the house, can then believe the necessary rapport and trust is in place. The part of self reporting and trusting may experience themselves as quite separate, maybe with their own body, and they consider the other mad mistrusting one over there to be somebody else.

However, that mad part and those littles and those introjects are actually part of the self (which fact is part of the preparation, ideally), and they may not trust. They feel separate, they are behind locked doors in the client's "house" of the self. That's how dissociation works.

There is the ANP/s (Apparently Normal Personality/ies) and the EP/s (Emotional Personality's). The whole self needs to be brought into the work and needs to function as a team with collaboration and communication within before ever doing EMDR. The ANPs often "do life." They face forward, facing life and the world, like a porch, but the price of acting normal and apparently trusting is to be out of touch with the internal condition of the house. The attic and basement may hold secrets or pain.

So those parts that DON'T trust need a chance to voice their concerns, which are there for good reason no doubt, and reasons that can be understood. Often those reasons are related to past needs for protection to survive. If they have never been voiced or heard -- even by the front or ANP part of the self -- the air back there gets pretty stagnant!! Kind of like King Tut's tomb, which hadn't been opened in 5000 years. EP's can often be disoriented in time, and not know it is 2007, and not 1978 or whatever.

Ego State Therapy gives a voice to those concerns, and enables solutions to be negotiated that are relevant to PRESENT time and situations, and that take into consideration the entire self with its many rooms, not just the porch!
Porches are important too, by the way, because facing forward, doing life and not knowing was very important.

In fact, the tactical integrationist approach of Catherine Fine enables that to continue while the work behind any amnesia barrier detoxifies the trauma, but that's another story for another day. Somebody remind me sometime when I have time I'll describe that. It only applies to DID, not DDNOS.