As cpanelkenneth told you in not so many words, virtual directory support with PHP is really a feature designed for MS Windows based platforms.
You can get limited functionality under Apache over Linux but only if your PHP is setup as a DSO (Apache Module) and even then it won't be the full virtual directory functionality subset.
Really your best bet would be to use a set of creative mod_rewrite commands in your .htaccess file to manipulate URLs as that can give you essentially the same functionality but by different means.