Custom menus does not show in Twenty Ten

Hi,

I′m testing WordPress features using Twenty Ten default theme. The theme include support for custom menu but when I create a custom menu, fill with links and specify this menu as primary menu the menu does not show in the header, just disapear.

?What can I do?

I just review some tutorial looking for a missing step but everything looks fine, aparently.

The menu load code is:

`wp_nav_menu( array( ‘container_class’ => ‘menu-header’, ‘theme_location’ => ‘primary’ ) );