Global custom menu in huge network

I’m having trouble finding a solution that works. I’m working on a site that has 100 network sites, and we need to have the same custom menu on all the sites – is there a way to do this? Maybe some code I can add to the template? I tried this code I found in the forums, but it didn’t work at all:

<?php switch_to_blog(1); ?>
<?php wp_nav_menu( array( 'theme_location' => 'sub-menu', 'sort_column' => 'menu_order', 'container_class' => 'menu-sub' ) ); ?>
<?php restore_current_blog(); ?>

It still shows the same default menu so I don’t know what else to try.

Thanks in advance ~