Woah. That is some very, very tough stuff you are going through.
My first question is: Do you have the option of not accepting the inpatient treatment, or do these people have the ability to have you involuntarily committed?
Second question: can you appeal to experts in the field of dissociative disorders? Can you get second / third opinions to counter theirs? I know there is a committee working on the dissociative disorders section in the new DSM - perhaps an email to them could put you in contact with someone who can help.

If I were your therapist I would not want to stay with that agency, that's for sure. Working for people who don't trust or respect your professional judgement is not anyone's idea of an ideal job.

The are differences, but your story is quite similar to my own. What happened in my case was my therapist left her agency and moved to private practice, where I saw her for another 3 years.
I truly hope this all works out well for you. It must be a very scary place to be in right now.