Raw json in chronograf post alert handler message

the problem is simple. Imagine I need to post a message to rabbitmq rest api from chronograf post alert handler.
It is so simple, I set http endpoint and I set json in message.
But, guess what, it does not work because chronograf put the message in another json tag so I cannot decide what I want to send but I have to send what chonograf wants.
Is it possible to change this behaviour? But note I do not want to write myself a flux script, I want to use chronograf gui.
Thanks in advance,