header("Location: http://server.com/");
header("Extra-info: Don't know how to fake referal and I want to hack your system");
header("Why: Because I'm a bad ass hacker");
header("What-can-we-do-for-you: Please consider using '$custom_referer' as a referal page");
Some servers might not be completely compatibile with this kind of headers, but you can first test it with http://www.cia.gov/
Oh, and you don't need to send me money for this. I don't want it to be fake as your referals...