In httpd.conf:
----------------------
  PerlConfigRequire "conf/startup.pl"
----------------------

In conf/startup.pl:
----------------------
  use Apache2::ServerUtil();

  my $config = '';
  foreach my $site (@sites) {
    $config.= = <<CONFIG;
        NameVirtualHost $site->{ip}:80
        <VirtualHost $site->{ip}:80>
            ServerName $site->{name}
            # Other config details
        </VirtualHost>
  CONFIG

  my $server = Apache2::ServerUtil->server;
  $server->add_config([split /\n/, config]);
----------------------