Validatebox - set valid status manually

[mazvv]

Hello.
In my application I'm using server side validation and return validation results using json. All my inputs are extends from validatebox such as comboboxes, numberboxes, numberspinner. How I can set error status for inputs manualy? I mean something like validationbox('isValid', false). now my code looks like:

Code:

				    	$.each(json.errors, function(i, item) {
				    		if(item){
				    			form.find('#'+i).addClass('error').attr('original-title',item);
				    		}
				    	});