Just for the files:
Meanwhile I just grabbed the missing IDs per plain mySQL-queries:
$config->usersPageIDs = array(29);
$new_users = array();
$xyz_db = new PDO('mysql:host=localhost;dbname=bzzzzt;charset=utf8', 'root', 'root');
$xyz_stmt = $xyz_db->query("SELECT templates_id, id FROM pages WHERE templates_id = 46");
$xyz_results = $xyz_stmt->fetchAll(PDO::FETCH_ASSOC);
foreach ($xyz_results as $row) {
$this_id = $row["id"];
$new_users[] = $this_id;
}
$xyz_db = null;
$config->usersPageIDs = array_merge($new_users, $config->usersPageIDs);
(I just figured that this could be simplified ... ... later ...)
blynx's post in Regarding "$config->usersPageIDs" of new user templates in 2.5.14, the right hook? was marked as the answer