How do i use X-Accel-Redirect with nginx

I have a asp.net website and i have nice urls so the user may see /abc/1/a.jpg the path is docroot/abc/number/number/id.jpg

I need asp.net to decode where the real path is. So essentially i do it and instead of rewriting i set the X-Accel-Redirect header and called Reponse.End(); I got a 404 error. This code was in Application_BeginRequest. I tried not doing .End() and just return. I get a asp.net like 404 error. I messed around and gave up so instead of sending the header i called HttpContext.Current.RewritePath to the exact same path. The ima开发者_开发技巧ge now displays but its being handled by asp.net instead of nginx.

How do i get nginx to listen to my X-Accel-Redirect headers? What do i need in my config file? my current one looks like this

Note that i am in fact putting everything through asp.net.

server {
    server_name www.MYSITE.com static.MYSITE.com;

    root /var/www/MYSITE;

    location / {
        fastcgi_pass   127.0.0.1:9000;
        fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
        include        fastcgi_params;
    }
}

---

gah. The problem was nginx config file. I needed to add

location /base/path {
    internal;
}

The file must be in a directory/location that is marked internal; I notice the content type is incorrect unless set to "". Heres what i did and i am not sure you need the first line

HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.ContentType = "";
HttpContext.Current.Response.AddHeader("X-Accel-Redirect", full);
HttpContext.Current.Response.End();