Adding your own panel layouts

I am trying to add a new panels layout, but I cannot get it to appear in the list of available panel layouts. Here is my two_main_sidebar.inc file in my two-main-sidebar folder that follows all the same patterns as the layouts folders in the main Zen theme folder. I get no errors or anything. I've flushed the caches and even tried putting my folder (and renaming things as appropriate) in the main Zen folder. I have the appropriate line in my .info file to include the my subtheme's layouts folder as well.

function subtheme_two_main_sidebar_panels_layouts() {
  $items['two_main_sidebar'] = array(
    'title' => t('Subtheme Layout: two main content with sidebar'),
    'icon' => 'two-main-sidebar.png',
    'theme' => 'two-main-sidebar',
    'admin theme' => 'two-main-sideb-aradmin',
    'css' => 'two-main-sidebar.css',
    'admin css' => 'two-main-sidebar-admin.css',    
    'panels' => array(
      'content1' => t('Content 1'),
      'content2' => t('Content 2'),
      'sidebar' => t('sidebar'),
    ),
  );

  return $items;
}