How to add breadcrumb?
Could you get what you want from the Custom Breadcrumbs module?


  Allows administrators to set up parametrized breadcrumb trails for any
  node type. This allows CCK-style node types to have "Home > User Blog
  >2005 > January" style breadcrumbs on the node view page itself, synchronizing cleanly with custom views or pathauto aliases.
  Breadcrumb visibility can be customized via a php snippet.