Query Custom taxonomy in wordpress 3

Hey, I got a small problem that I am unable to solve, hope someone can help me on this:

I am using the WP3 RC 1 Version and registered a new post type along with a new taxonomy for that type:

add_action('init', 'portfolio_register');

	function portfolio_register() {
		  $labels = array(
		    'name' => _x('Portfolio Items', 'post type general name'),
		    'singular_name' => _x('Portfolio Entry', 'post type singular name'),
		    'add_new' => _x('Add New', 'portfolio'),
		    'add_new_item' => __('Add New Portfolio Entry'),
		    'edit_item' => __('Edit Portfolio Entry'),
		    'new_item' => __('New Portfolio Entry'),
		    'view_item' => __('View Portfolio Entry'),
		    'search_items' => __('Search Portfolio Entries'),
		    'not_found' =>  __('No Portfolio Entries found'),
		    'not_found_in_trash' => __('No Portfolio Entries found in Trash'),
		    'parent_item_colon' => ''
		  );

    	$args = array(
        	'labels' => $labels,
        	'public' => true,
        	'show_ui' => true,
        	'capability_type' => 'post',
        	'hierarchical' => false,
        	'rewrite' => true,
        	'show_in_nav_menus'=> false,
        	'menu_position' => 5,
        	'supports' => array('title','thumbnail','excerpt','editor')
        );

    	register_post_type( 'portfolio' , $args );

    	register_taxonomy("portfolio_entries",
					    	array("portfolio"),
					    	array(	"hierarchical" => true,
					    			"label" => "Portfolio Categories",
					    			"singular_label" => "Portfolio Categories",
					    			"rewrite" => true,
					    			"query_var" => true

					    		));  

	}

now when i use query_posts(post_type=portfolio) that works fine but i need to select the different categories as well wich doesnt work:

query_posts(post_type=portfolio&cat=2,3,4)

did i forget to set any arguemnts that are neccessary? Thanks for your help!
Regards Kiraa