I am fairly certain there is no where in there to set an alert on replies. I modified the code to make this happen. I set it up so the admin gets the same email that the client does.
In include/class.ticket.php ~ line 580 AFTER
}else {
$deptemail=$dept->getEmail();
if(!$deptemail || !($from=$deptemail->getAddress()))
$from=$cfg->getDefaultEmailAddress();
//Reply separator tag.
if($cfg->stripQuotedReply() && ($tag=$cfg->getReplySeparator()))
$body ="\n$tag\n\n".$body;
}
Misc:($this->getEmail(),$subj,$body,$from,$fromName,$headers);
ADD this
Misc:($cfg->getAdminEmail(),$subj,$body,$from,$fromName,$headers);