omega breadcrumbs forums zen

I'm a novis to Omega and Drupal, but how to make the 'breadcrumbs' work under 'forums' ?

In 'ZEN' (and my subtheme of that) for example this works just fine, but then I switch to my Omega subtheme it don't. One way I have tried is to copy/paste Zen's 'function zen_breadcrumb($variables) {' into my subthemes template.php but it will not run. Hope someone can explain how to make it run or an other solution...