use strict;
use warnings;
use XML::Simple;

my $xs = XML::Simple->new(ForceArray=>['httpd']);
my $s = do { local $/=undef; <DATA> };
my $conf = $xs->XMLin($s);
my $ct = 0;
foreach my $httpd ( @{$conf->{httpd}} ){
  $ct++;
  if( ref($httpd) eq 'HASH' ){
    $httpd->{number} = $ct;
  }else{
    $httpd = { content=>$httpd, number=>$ct };
  }
}
my $xml = $xs->XMLout($conf);
print $xml;


__DATA__
<x>
<httpd><![CDATA[
...1st piece of httpd configuration
]]></httpd>
<httpd><![CDATA[
...2nd piece of httpd configuration
]]></httpd>
</x>