To avoid duplication of menus, and since the menu structure is well defined, we chose to use only one menu and adapt it to varoius block (main menu, breadcumb, footer).
To create a custom theme for a menu, we create a function in template.php of this type:
function valencia_[block_name]_menu($vars) {
// Custom menu
}
$vars is an array, which contain a $link index with all links in the menu (TO-DO: find reference on Drupal guide and insert here)
To register the new function we need to modify valencia_links__system_main_menu in template.php, adding to switch the new function.
To call the new function use:
print theme('links__system_main_menu', array(
'links' => $valencia_menu,
'id' => 'footer'
));
where links is an array with all links in the menu (and other property, see Drupal documentation) and id is the name of the block, as declared in the new function.