Triggers before comment is deleted.

<?php
function my_component_init(){
		ossn_register_callback('comment', 'before:delete', 'my_component_cb');
}
function my_component_cb($callback, $type, $params){
		// $params['comment'] contains ID of comment (not instance)
}
ossn_register_callback('ossn', 'init', 'my_component_init');