edit template with plugin

[harmor19]

Is it possible to edit a template with a plugin?
Here's a code from another BBS that uses the plugin system

PHP Code:

require "./inc/adminfunctions_templates.php";
    find_replace_templatesets("header", '#help</a></li>#', "help</a></li><li><a href=\"\$settings[bburl]/\$settings[cpphpfn]\"><img src=\"\$theme[imgdir]/star.gif\" border=\"0\" alt=\"Custom Pages\">Custom Pages</a></li>"); 


"header" is the template it's editing,
It changes "#help</a></li>#" to help</a></li><li><a href=\"\$settings[bburl]/\$settings[cpphpfn]\"><img src=\"\$theme[imgdir]/star.gif\" border=\"0\" alt=\"Custom Pages\">Custom Pages</a></li>