How to *KEEP* PHP pages in cache?

Hello, using: *nix/Apache 1.3.12/PHP 4.02 All of the dynamic content goes only to memory cache. Without using the "get" method (which would show the user's password in the URL), I want the user to hit the "back" button without getting the infamous "Missing POST" message. I have been to http://www.mnot.net/cache_docs/, which says: By default, objects processed by PHP are not assigned validators, and are therefore uncacheable. However, developers can set HTTP headers by using the Header() function. I've tried the Header function, but when I do View Info in Netscape, it still says, "Currently in memory cache." Any help is greatly appreciated! -- Paul Fernandez Webmaster Structural GenomiX, Inc. www.stromix.com 858.558.4850