private function get_model_instance($model_classname)
	{
	    if(!isset($this->controller->{$model_classname}))
		{
			/*
			 * Do not use $this->controller->loadModel, as calling it from a plugin may prevent correct loading of behaviors
			 */
			$model_instance = ClassRegistry :: init($model_classname);
		}
		else
		{
			$model_instance = $this->controller->{$model_classname};
		}
		
		return $model_instance;
	}