s2Member PHP calls with 3rd Party Plugin

I have just installed a plugin that allows me to write snippets of PHP that can be executed on a page or post by using an associated shortcode.

The plugin is “PHP Code for posts” v1.1.3 By The Missing Code
http://wordpress.org/plugins/php-code-for-posts/

This works great but it does not work with any of the PHP I find at
http://www.s2member.com/codex/stable/s2member/api_functions/package-functions/

I assume that I have to hook into the s2member functions somehow but I do not understand s2member and WordPress well enough to be able to figure this out on my own. Seems like it should be a simple require or include like…

require(‘s2member.php’);

…but I’m guessing that with WordPress it will not be that simple….

Thanks to anyone who can help.

I found the answer, and that was to swicth over to the PHP Execution plugin at
http://wordpress.org/plugins/php-execution-plugin/

…works like a charm.