disable="false" instead of
disable="". I can easily use the Firebug console to achieve this.
About the comment. I do not have a reputation high enough to post an answer to my own question. If someone know how to use ZAP for editing http responses I would be glad to hear it. It seams to me like its not working but ZAP gives the user the impression that it should be working. Please confirm my suspicion(that this functionality do not exist) or answer how to do it.