I've set up an Apache 2.2 server as forward proxy using mod_proxy and mod_proxy_http

During my application that utilizes that proxy I have to modify http demands. (Demands means the request that would go to the foundation server from the content. I shouldn't manipulate the response that dates back towards the client)

I'm already sucessfully changing/adding snacks using RequestHeader from mod_headers.

I'm also adjusting GET data using RewriteRule from mod_rewrite.

Now my real question is whether there's a method to alter publish data.