How to preseed install via pppoe (for A-DSL)?

[Josef Wolf <jw@raven.inka.de>]

Hello!

I am trying to create a customized install cd (based on ubuntu-7.10
alternate install cd).

Everything works as desired so far.  Just one problem remains:  On the
installed box, d-i needs to run "pppoeconfig eth1" before it configures
apt-sources.  Without this, apt configuration fails because no
repositories are available.

I have seen that ppp, pppoe and pppoeconfig packages are already contained
on the alternate cd.  Thus the only missing thing seems to be to run

    dpkg -i /cdrom/pool/p/ppp* && pppoeconfig eth1

at the right time just before apt-repositories are configured.  It seems
that preseed/early_command is much too early and preseed/late_command
is too late.  Where would the proper place be to hook this command?

Anybody already done this?  Any hints?