public static function onload($instance_identifier, $callback, $ignore_instancename = false) {
		$args = func_get_args();
		
		// get instance name in params string
		$params		= explode(':', $instance_identifier);
		$classname	= $params[0];
		
		// we always have to create a fully namespaced class path
		if ($classname{0} !== '\\') {
			$classname = '\\Morrow\\' . $classname;
		}

		// use the instancename or the last part of the classname for saving the args
		$instancename = (isset($params[1])) ? $params[1] : '_morrow_default';

		// save callback
		if ($ignore_instancename) {
			self::$_onload_callbacks[$classname][] = $callback;
		} else {
			self::$_onload_callbacks[$classname . ':' . $instancename][] = $callback;
		}
	}