It shouldn't be that hard...
First, replace line 275 on 'viewtopic.php' with:
'SELECT' => 't.subject, t.posted, t.poster, t.first_post_id, t.closed, t.num_replies, t.sticky, f.id AS forum_id, f.forum_name, f.moderators, fp.post_replies, u.realname',
Next, replace line 317 from the same file with:
if ($cur_post['realname'])
$forum_page['post_ident']['byline'] = '<span class="post-byline">'.sprintf((($cur_post['id'] == $cur_topic['first_post_id']) ? $lang_topic['Topic byline'] : $lang_topic['Reply byline']), (($forum_user['g_view_users'] == '1') ? '<a title="'.sprintf($lang_topic['Go to profile'], forum_htmlencode($cur_post['username'])).'" href="'.forum_link($forum_url['user'], $cur_post['poster_id']).'">'.forum_htmlencode($cur_post['realname']).'</a>' : '<strong>'.forum_htmlencode($cur_post['realname']).'</strong>')).'</span>';
elseif ($cur_post['poster_id'] > 1)
And... you're done! (It worked for me)