Additional custom taxonomy on jetpack portfilio not showing up as metabox

Hello I try to add my own taxonomy for the jetpack portfolio post-type like this:

In my function.php:

tpack portfolio post-type like this:

In my function.php:

add_action( 'init', 'fh_portfolio_taxonomy');
 
function fh_portfolio_taxonomy() {
 
  $labels = array(
    'name' => _x( 'Materialien', 'taxonomy general name' ),
    'singular_name' => _x( 'Material', 'taxonomy singular name' ),
    'search_items' =>  __( 'Materialen suchen' ),
    'all_items' => __( 'Alle Materialien' ),
    'parent_item' => __( 'übergeordnetes Material' ),
    'parent_item_colon' => __( 'übergeordnetes Material:' ),
    'edit_item' => __( 'Material bearbeiten' ), 
    'update_item' => __( 'Material aktualisieren' ),
    'add_new_item' => __( 'Neues Material anlegen' ),
    'new_item_name' => __( 'Materialname' ),
    'menu_name' => __( 'Materialien' ),
  );    
 
  register_taxonomy('jetpack-portfolio-material','jetpack-portfolio', array(
    'hierarchical' => false,
    'labels' => $labels,
    'public' => true,  
    'show_ui' => true,
    'show_admin_column' => true,
    'show_in_nav_menus' => true,  
    'query_var' => true,
    'rewrite' => array( 'slug' => 'material' )
  ));
	
register_taxonomy_for_object_type('jetpack-portfolio-material', 'jetpack-portfolio');
	
}

The extra taxonomy menu item on the main navigation on the left side is there and I can edit my “Material” stuff, but it doesn’t appear as a metabox in the portfolio post on the right side (beside revision, excertp, etc.).

Is there a trick to get it also as a normal metabox to be able to assign the “Material” inside the portfolio post? The metabox is totaly missing.