CakePHP v2.x validate HABTM

AppController.php

public function beforeRender() {
	// Enable HABTM validation
	$model = Inflector::singularize($this->name);
	foreach($this->{$model}->hasAndBelongsToMany as $k=>$v) {
		if(isset($this->{$model}->validationErrors[$k]))
		{
			$this->{$model}->{$k}->validationErrors[$k] = $this->{$model}->validationErrors[$k];
		}
	}

}

AppModel.php

public function beforeValidate() {
	foreach($this->hasAndBelongsToMany as $k=>$v) {
		if(isset($this->data[$k][$k]))
		{
			$this->data[$this->alias][$k] = $this->data[$k][$k];
		}
	}
}

Model.php

public $validate = array(
	'Type' => array(
		'multiple' => array(
			'rule' => array('multiple',array('min' => 2)),
			'message' => 'Please select at least 2 types'
		),
	),
);