Use of apt-proxy with net install of sarge

[Paul E Condon <pecondon@peakpeak.com>]

I have a recently downloaded and burnt sarge net install CD.
I would like to test it in my environment. My internet access
is ppp on one of my debian boxes. I have apt-proxy running on
that box and I have done a dist-upgrage to sarge on one of my
computers, so the apt-proxy should have cached copies of most
of what needs to be downloaded during a net install. But, I
can't figure out what I should tell the netinstall software
when it asks me to specify a mirror. Some particulars of my
system:

The url of the host running apt-proxy is cmn.lan.gnu .
A sample line in a using host sources.list is 
    deb http://cmn.lan.gnu:9999/main woody main contrib non-free
The cache location line in apt-proxy config file is
    APT_PROXY_CACHE=/sdb5/cache/apt-proxy
I have NAT, bind9, and DHCP deamon configured and running.

What do I type on a newly attached machine to get it to make use
of the apt-cache for a net install of sarge? Or is this proto-feature
not implemented?

-- 
Paul E Condon           
pecondon@peakpeak.com