We're using Lighttpd as our server and not Apache.
From what I can see, it does not support any methods for grabbing and exclude the X-GT-Lang header from redirects to www.
Lighttpd only has the following conditions:
cookie, host, useragent, referer, url, querystring, remoteip, request-method, scheme (http/s), and language.
Is there anything among these we can use to stop redirects for X-GT-Lang?