Use hook_islandora_tabs() to add ALL the tabs.

...  Including those provided by islandora proper.

fedora_repository.module

@@ -951,6 +951,63 @@ function makeObject($pid, $dsID) {
   $objectHelper->makeObject($pid, $dsID);
 }
 
+/**
+ * Implementation of hook_islandora_tabs().
+ * 
+ * @param $content_models array
+ *   An array of ContentModel objects to which the current Fedora Object
+ *   subscribes.
+ * @param $pid string
+ *   A string containing the Fedora PID of the current Fedora Object.
+ * @param $page_number integer
+ *   An integer for which page we should start on in the loaded object.
+ * @return array
+ *   An array containing a tabset (an array of tabpages), renderable with
+ *   drupal_render().
+ */
+function fedora_repository_islandora_tabs($content_models, $pid, $page_number) {
+  $cmodels_tabs = array(
+      '#type' => 'tabset',
+  );
+  
+  foreach ($content_models as $content_model) {
+    $content_model_fieldset = $content_model->displayExtraFieldset($pid, $page_number);
+    
+    // Each content model may return either a tabpage array or plain HTML. If
+    //  it is HTML, stick it in a tabpage.
+    if (is_array($content_model_fieldset)) {
+      $cmodels_tabs = array_merge($cmodels_tabs, $content_model_fieldset);
+    }
+    else {
+      $cmodels_tabs[$content_model->pid] = array(
+          '#type' => 'tabpage',
+          '#title' => $content_model->name,
+          '#content' => $content_model_fieldset,
+      );
+    }
+  }
+  
+  // Add a 'manage object' tab for all objects, where detailed list of content is shown.
+  // XXX:  Perhaps this should be extracted into its own object?
+  module_load_include('inc', 'fedora_repository', 'plugins/FedoraObjectDetailedContent');
+  $obj = new FedoraObjectDetailedContent($pid);
+  
+  //can disable showing the object details tab in admin UI
+  if (variable_get('fedora_repository_show_object_details_tab', TRUE)) {
+    $object_details = $obj->showFieldSets();
+    if ($object_details['fedora_object_details']['#selected'] == TRUE) {
+      foreach (element_children($cmodels_tabs) as $key) {
+        $cmodels_tabs[$key]['#selected'] = FALSE;
+      }
+    }
+  }
+  else {
+    $object_details = array();
+  }
+  
+  return array_merge($cmodels_tabs, $object_details);
+}
+
 /**
  * Sends an ITQL query to the Fedora Resource index (can only communicate with Kowari or mulgara)
  * Reads the pid and datastream id as url parameters.  Queries the collection object for the query
@@ -984,7 +1041,7 @@ function fedora_repository_get_items($pid = NULL, $dsId = NULL, $collection = NU
     $pid = variable_get('fedora_repository_pid', 'islandora:root');
   }
 
-  $item = new fedora_item($pid);
+  $item = new Fedora_Item($pid);
   if (!$item->exists()) {
     drupal_not_found();
     exit();
@@ -1023,57 +1080,19 @@ function fedora_repository_get_items($pid = NULL, $dsId = NULL, $collection = NU
     return makeObject($pid, $dsId);
   }
 
-  $content = '<div id="content-fedora">';
-
-  module_load_include('inc', 'fedora_repository', 'CollectionClass');
-  $collectionClass = new CollectionClass();
-  module_load_include('inc', 'fedora_repository', 'ContentModel');
-  module_load_include('inc', 'fedora_repository', 'plugins/FedoraObjectDetailedContent');
   $breadcrumbs = array();
   $objectHelper->getBreadcrumbs($pid, $breadcrumbs);
   drupal_set_breadcrumb(array_reverse($breadcrumbs));
 
-  $offset = $limit * $page_number;
   $content_models = $objectHelper->get_content_models_list($pid);
-// Each content model may return either a tabset array or plain HTML. If it's HTML, stick it in a tab.
+  
+  $hook_tabs = module_invoke_all('islandora_tabs', $content_models, $pid, $page_number);
+  
   $cmodels_tabs = array(
     '#type' => 'tabset',
   );
-  foreach ($content_models as $content_model) {
-    $content_model_fieldset = $content_model->displayExtraFieldset($pid, $page_number);
-    if (is_array($content_model_fieldset)) {
-      $cmodels_tabs = array_merge($cmodels_tabs, $content_model_fieldset);
-    }
-    else {
-      $cmodels_tabs[$content_model->pid] = array(
-        '#type' => 'tabpage',
-        '#title' => $content_model->name,
-        '#content' => $content_model_fieldset,
-      );
-    }
-  }
-  
-// Add a 'manage object' tab for all objects, where detailed list of content is shown.
-  $obj = new FedoraObjectDetailedContent($pid);
-  
-  //can disable showing the object details tab in admin UI
-  if (variable_get('fedora_repository_show_object_details_tab', TRUE)) {
-   $object_details = $obj->showFieldSets();
-   if ($object_details['fedora_object_details']['#selected'] == TRUE) {
-     foreach ($cmodels_tabs as &$cmodel_tab) {
-       if (is_array($cmodel_tab)) {
-         $cmodel_tab['#selected'] = FALSE;
-       }
-     }
-   }
-  }
-  else {
-   $object_details = array();
-  }
-
-  $hook_tabs = module_invoke_all('islandora_tabs', $content_models, $pid, $page_number);
-  $cmodels_tabs = array_merge($cmodels_tabs, $object_details, $hook_tabs);
   
+  $cmodels_tabs = array_merge($cmodels_tabs, $hook_tabs);
   return tabs_render($cmodels_tabs);
 }