Need help to install packages from external repository during CentOS install

[Craig Huff]

About a week ago it was suggested that I use a kickstart file to
install packages from an external repository (ATrpms) during CentOS
5.1 installs, so I have been giving it a go, unsuccessfully.  I
finally got enough information from the failures to figure out the
problem, but I don't know what the solution is.  It appears that
despite having this:

network --device=eth0 --bootproto=dhcp

in the command section, the network is not working during %post
execution and probably not during the system installation phase,
either.  I have tried installing nvidia-graphics169.07 (and the
related pieces) in several ways, none of which worked.

The first approach was to add this:

repo --name=atrpms
--baseurl=http://129.102.1.25/pub/atrpms/el5-i386/atrpms/stable

in the command section and this:

nvidia-graphics169.07

in the %packages section, but this failed.  Note that the IP was used
after several attempts to use dl.atrpms.net failed and I then
discovered in the Installation Manual that, since I was using DHCP,
name resolution was not working during the installation (or %post
phase, for that matter).

The second approach was to keep the repo --name... statement in the
command section and use this for a (simplified) %post script:

%post
( #Note: using subshell for logging, but it never works.
yum -y --disablerepo=extras install nvidia-graphics169.07
) 1>/root/Anaconda_post.log 2>&1

Finally, I dropped the repo --name... statement from the command
section and tried copying from the kickstart medium an atrpms.repo
file into /etc/yum.repos.d that looked like this:

[atrpms]
name=ATrpms for RHEL and CentOS $releasever - $basearch
baseurl=http://129.102.1.25/pub/atrpms/el$releasever-$basearch/atrpms/stable
enabled=1
gpgcheck=0

however, even this failed.  Then, using the screen accessed with (I
think) ctrl-alt-F2 which offered a shell, I tried it manually and
discovered that the networking wasn't configured and (once I su'd to
root), ifconfig -a reported the devices had no IP addresses.

So, what do I do differently to get a kickstart file that will
successfully install RPMs from ATrpms?

I *could* install with a static IP, which may fix this problem, but my
understanding is that the installed system would *also* be configured
with the static IP, which is not what I want.

Any help appreciated.

Craig.