To add a profile subpage like /u/user/edit you can use this hook. You also need to use a ossn_profile_subpage(page name);

<?php
function my_component_init(){
		ossn_add_hook('profile', 'subpage', 'my_component_hook');	
		ossn_profile_subpage('newsubpage');
}
function my_component_hook($hook, $type, $return = null, $vars){
		//$vars['user'] contains user instance (OssnUser)
		if($vars['subpage'] == 'newsubpage'){
			return 'your new page';
		}
}
ossn_register_callback('ossn', 'init', 'my_component_init');