There is no key to do so. You need to get it from the DB as it is a user field.
Open the qa-include/qa-app-format.php file and try this code. Green lines are the new added ones:
if (isset($postuserid) && isset($usershtml[$postuserid])) {
$whohtml=$usershtml[$postuserid];
if ($microformats)
$whohtml='<span class="vcard author">'.$whohtml.'</span>';
$userprofile = qa_db_select_with_pending(qa_db_user_profile_selectspec($postuserid, true));
if (isset($userprofile['name']) && !empty($userprofile['name'])) {
$whohtml .= ' (' . qa_html($userprofile['name']) . ')';
}
} else {
It's worth mentioning that it is better to write a plugin rather than adding a core hack but that will be more complex :)