Here's the code I use and works.
PHP:
<html>
<head>
<title>Sponsor blah</title>
<meta name="robots" content="noindex,nofollow">
<script>window.location="http://www.sponsor.com/aff-id.php";</script>
<meta http-equiv="refresh" content="1; url=http://www.sponsor.com/aff-id.php">
</head>
<body>
<p align="center">You are being taken to the correct page.
<br>If the page does load after 5 seconds,
<a href="http://www.sponsor.com/aff-id.php">click here to go to affiliate site</a>.</p>
</body>
</html>
Then save the file naming it after your sponsor or tracking id.
I then upload it to a directory named "ref" or "go"
So the final look of the url would look like this:
http://www.your-domain.com/go/aff-program.php
If your sponsor has referal tracking all you will see is that URL, to be more sneaky you can always do the redirect from a different domain and server and they will have to work hard to find your top notch landing page.