Hiding menu items is easy when you're using a regular mod_mainmenu -- you just replace that menu with the mod_mainmenu_juga.

But what about when you're using a styled menu module?

Many of the available Joomla! templates use their own modules for displaying your menus, which makes it difficult for us to release a single module that works on all sites.  As a result, to get your themed template to hide Menu Items, you will have to make a few changes to the template's PHP code.

One of our users, vanboke, has published his method for modifying a YooTheme template to work with JUGA in order to hide menu items.  The original post is here: http://www.dioscouri.com/forum/func,view/id,2207/catid,4/#2207

Thanks, vanboke!