Returning headers from FastCGI

[Johan Bergström]

I'm using Nginx (.7.x) as a simple proxy where a couple of FastCGI  
applications acts as lookup tables. These apps returns which proxy  
backend that should have the request through X-Accel-Redirect - eg / 
backend1/$new_uri. Finally I catch these in location matches and pass  
the request along with proxy_pass.

Since i scrub the $new_uri somewhat, I want to send additional info  
as a header back to Nginx, but I can't make this work. How do I pass  
headers from FastCGI back to Nginx?

Kind Regards,
Johan