How to create a custom menu I have created a menu called "navbar". In this menu, there is 4 links at level 1. Each of these links has 3 sublinks (level 2). All links in the menu point to a different page.
For example, I have on lvl 1 "Projects" (that points to /projects). That parent links contains 3  lvl 2 subsections : "News" (projects/news), "Photos" (projects/photos) and "Maps" (projects/maps).
Then I create an article, I check the "Provide a menu link" and I select "News" in the dropdown list.
I have "menu block" installed, and I configured a "navbar" block to be bound to the "navbar" menu. I also installed "menu node" to have a table with the mapping between nodes and menus.
Now, how do I customize the menu to display all lvl 1 &amp; 2 and all associated articles ? What function do I need to create and where ?
I have tried the following code to no avail (where business is my theme's name and 2 is the menu id) : 

function business_menu_link__menu_block__menu_navbar($variables)
function business_menu_tree__menu_block__menu_navbar($variables)
function business_menu_link__menu_block__2($variables)
function business_menu_tree__menu_block__2($variables)


What should I do ?
Ok I found what was wrong :
I needed to register the function in the template.php :

function business_theme_registry_alter(&amp;$theme_registry) {
    $theme_registry['menu_tree__menu_block__menu_navbar']['function'] = 'business_menu_link__menu_block__menu_navbar';
}
function business_menu_link__menu_block__menu_navbar($variables) {

}