multipart/x-mixed-replace not working

I have a internet camera that returns a  multipart/x-mixed-replace 
stream. It sort of goes:

$ wget -S http://192.168.1.150/video.cgi
--17:20:29--  http://192.168.1.150/video.cgi
            => `video.cgi.3'
Connecting to 192.168.1.150:80... connected.
HTTP request sent, awaiting response...
  1 HTTP/1.0 200 OK
  2 Server: Camera Web Server/1.0
  3 Auther: Steven Wu
  4 MIME-version: 1.0
  5 Cache-Control: no-cache
  6 Content-Type:multipart/x-mixed-replace;boundary=--video boundary--

$ head video.cgi.3
--video boundary--
Content-length: 57674
Content-type: image/jpeg

    : etc


Reading about multipart/x-mixed-replace as a server push protocol 
(http://wp.netscape.com/assist/net_sites/pushpull.html), I get the idea 
that each new jpeg in the stream should replace the previous one being 
viewed. However, on my Mozilla 1.7, only the first jpeg image is 
rendered. Trying IE6, just for grins, it never even renders the first image.

Is there a browser setting I am missing, or is the old Netscape document 
description invalid?