Insert topic count from advanced_forum_topic_list view.

Hi all. I'm using the advanced_forum_topic_list view, and i've grouped the list by term id (in view settings, after select 'forum topic list').
Now i want to show the count of topic per term name, like in the /forums page, but i can't use the variable $item->total_topics, like in forum-list.tpl.php.
After adding a relationship to the term, I tried to find some count field to add to the view, but i've not finded nothing to achieve this.
What i have to do?
Thanks,
edubacco