visitation by my 12 year old

My husband and I are separated but not yet divorced - I was hoping we could settle soon but he just gave me his version of a fair settlement agreement that had me giving him tens of thousands of dollars while he keeps the house and doesn't give me any of the equity.  Unfortunately I think we have a way to go while I'm trying not to be bitter and vindictive.
Anyway - that isn't why I wrote.  We have three children together, aged 12, 11 and 8.  I have custody of the kids - he has standard visitation.  None of the kids want to visit him although I strongly encourage them to go and have never given them the option for any other alternative.  I've explained to the kids that Daddy loves them very much but doesn't show love in the same manner as we do.  That is working for the younger two kids.
My 12 year old is desperately fighting each and every visitation visit.  In her words "I hate him and wish he would disappear".  When she gets there, she is sent to her room within 15 minutes, where she has to stay for the rest of the evening.  She is punished for locking her door, for calling me, for not answering his questions, for answering in a manner he finds disrespectful, etc.  She is the only one that gets punished each visit.  She calls me each visit hysterical - tonight it was because he let the younger two go to the pool while she had to go to her room.  Afterwards they had watermelon but she wasn't allowed to have any.
She has asked repeatedly how old she has to be to stop visiting him.  When I told her that the court doesn't like kids her age becoming alienated from a parent and would probably mandate counseling she becomes hysterical again saying she will not go to counseling with him.  Unfortunately I know from experience (3 years of marriage counseling) that for him, counseling is an opportunity to convince the therapist that he has been wronged.  Out of 3 therapists, none supported him in this.  They tried to help him see that I was trying to appease him and please him but he refused to acknowledge it.  If I did try to accomodate his "list of items that would make me [him] happy" he would change his needs.  He thought marital relations 3 times a week would make him happy - when he got that he decided it needed to be 7 to 8 times a week.
Anyway - I'm afraid counseling between my daughter and him would damage her further.  I'm also starting to worry that she is going to do something rash to hurt herself or to hurt him to get out of the visits.  What can I do?  Can she request no visits with him?  She has also asked if she can divorce him - is that possible?  I am so worried about her - I've tried to talk to him about it but he said that he is the adult and he doesn't have to do anything to accomodate her needs - it is her job to accomodate his needs and right now, he is demanding respect but refuses to respect anyone else.
I need help!!!