I wrapped an html page with the standard

include("../mainfile.php");
include(XOOPS_ROOT_PATH."/header.php");
//
include(XOOPS_ROOT_PATH."/footer.php");

which works fine except the main html content shows even if your not logged in, if you know or bookmark the URL. I've seen in other posts where you can test using;
if ($xoops_isuser)
but that variable and any other $xoops variables are not available from this page. Is there another file you have to include to use these variables for external html pages?