How can you put a user profile item in a category on the user's account information page? My attempt is:

function mymodule_user($op, &amp;$edit, &amp;$account, $category = NULL)
{
  switch($op)
  {
   (...)   
      case "view":
         $account-&gt;content['my_cat']['plant_1'] = array(
                    '#type' =&gt; 'user_profile_item',
                    '#title' =&gt; 'Plant 1',
                    '#value' =&gt; '42',                    
                    );     
  }


But that doesn't work as the 'Plant 1" form element appears at the top of the page without a category. The categories seem not to be derived from $op = "categories" where I defined 'my_cat'. So how can I tell Drupal that "Plant 1" should be in the my_cat category on the user account information pages?
In the meantime I've figured it out. The categories are also defined in the 'view' operation by using the type 'user_profile_category'. For example:

$account-&gt;content['my_cat'] = array(
          '#type' =&gt; 'user_profile_category',
          '#title' =&gt; 'Plants Summary',
         );