Missing http protocol

Hi all,
i want to use nbar in my cisco router 837 IOS ver 12.4(25d) (i know it's kind of old ), but when i use the command
#show ip nbar port-map
i get a bunch of protocols with port number :

........
port-map rsvp udp 1698 1699
port-map rtsp tcp 554
port-map secure-ftp tcp 990
port-map secure-http tcp 443
port-map secure-imap udp 585 993
......

but to my surprise no listing of the well known protocl http tcp 80 !!!
I need it in order to block some kind of http traffic using nbar
why is that !! how can I add support in nbar to that protocol


thanks for your help