I have never had one that exhibited this behavior, but if I did, and nothing else seemed to work I might try a staged carrot and stick approach. Since it would seem that she doesn't like the trailer I would start with the carrot. Teach her that the trailer is a good place to be by parking it in a area with her and always feeding her out of it. That is, place her feed and hay in there and let her go in and out of it of her own free will. It might also be good if the trailer was the only place she could get out of the sun in, or go into when it rained. It would be great if she sought it as shelter during a storm. Its important that she still get to visit her buddies and continue to be part of the herd on a regular and often basis though. Next try closing the doors with her in there for just a bit and when you take her out let her visit her buddies. Increase how long she has to stay in there a few times before she gets to go visit her buddies.
If she kicks its time to use the stick (not literally). In this case I would suggest a loud horn that was was blown near an open trailer window for just a half second or so as soon as she kicked. This would likely get her attention. I'd give the horn a short blast each time she kicked. If she was persistent I might increase the length of the blast a little, maybe to 1 second. I don't think I'd do this more than 3 times the first time I used it though. At the end of the session she would be let out and the session NOT repeated for a few days while she re-established her friendly relationship with the trailer. I don't think she would forget it though. Repeat the horn exercise until she will stay in the trailer without kicking for at least 10 minutes. Then its time to go to the next stage.
The next stage would be to take her in the trailer from her pasture/paddock to a very near pasture, maybe just through a gate which has been separating her from other horses/buddies. Let her out of the trailer into the pasture with her buddies for the day while you return the trailer to her paddock. At the end of the day ride or lead her back to her paddock where the trailer is for feeding. Then the next day, load her up and take her back to her buddies, again just a very short ride. Repeat this procedure but lengthening how long she is in the trailer each time.
Hopefully, she won't kick on the first very short rides and she will get the reward of getting to visit her buddies. If she does kick you may have to digress to setting up a horn in the trailer which you can operate from the truck.
This is obviously a rather involved and unusual process, but this is a bit of an unusual behavior, and you did ask for ideas.