Create a file proxy.pac and store it into your web server:

function FindProxyForURL(url, host) {
    if (shExpMatch(url, "http://remote.server.com:8084/subdir/page.jsp?query_string")) {
        return "PROXY your.server.org:8080";
    }
}

Configure the fake VirtualHost on your web server:

The put the fake file into the DocumentRoot fo the VirtaulHost /var/www/remote.server.com/subdir/page.jsp.

Configure the browser to use automatic proxy, and give http://your.server.org/proxy.pac as the URL.