In terms of 'mounting' all they did stock as use some silicon (?) or some adhesive to adhere it to the inner diameter of the airframe. Hope that makes sense and was what you were asking.
I attached some pics of the surgery to replace the elevator servo. I put in an HXT-500 since it was what I had but did require some modification. The servo lead was too short so I had to replace the lead with the one from the damaged servo. Not a very difficult change and probably saved some weight. Hopefully this replacement servo lasts a little longer