pear quickform multiple checkbox checked

	$checkobj = array();
		foreach($Categories as $h => $ValueC){	
			$checkobj = HTML_QuickForm::createElement('checkbox', $h ,null ,utf8_encode($ValueC['category']));
			if(count($CategoryGroups) > 0){
 
				foreach ($CategoryGroups as $KeyC => $ValC) {
					if($ValueC['id'] == $KeyC){	
						echo "<pre>";
						print_r($KeyC);
						echo "</pre>";	
						$checkobj->setChecked(true);
					}
				}
			}
			$checkboxen[] = $checkobj;
		}	
		$form->addGroup($checkboxen, 'categ', $_lang['daten']['category'], '', true);