I thought that the disappearance of IX Hispana has been debunked, or was based on faulty evidence. That some of the confusion was related to their quick deployment to the Lower Rhine or Nijemegen region in 122, and that this was the time of their supposed disappearance.
whoops, sorry, I didn't read yours until it was too late. :'o
http://www.freerepublic.com/focus/f-chat/1652869/posts?page=7#7