Thanks for the recommendation ,
I am using nginx as a reverse proxy on each one of my application server .
the reason I am doing it is , my application server connect to a backend system which can be available on 2 domains ,
the nginx as a reverse proxy on my application system verify that if one domain is down it automatically use the 2nd one which might be available .
The problem I am having is once the application server need to connect to the backend through a proxy server , the nginx dont know how to move the traffic through a proxy which require authentication and configuration .

I start check how complex will it be to update the nginx source code , Can anyone from the nginx team estimate how complex it will be if possible @ all ?