public function addElement( tao_helpers_form_FormElement $element, $isSystem = false)
    {

		$elementPosition = -1;
		foreach($this->elements as $i => $elt){
			if($elt->getName() == $element->getName()){
				$elementPosition = $i;
				break;
			}
		}

		if($elementPosition >= 0){
			$this->elements[$elementPosition] = $element;
		}else{
			$this->elements[] = $element;
		}

		if ($isSystem) {
		    $this->systemElements[] = $element->getName();
        }


    }