# This is free hand, please ignore typos:
   my $templateContents = { hosts => 
       {
          name = '[% host.name %]',
       },
       ...
   }

##</code><code>##

use strict ;
use warnings ;
use Template ;
my $file = 'template.xml.tt';
my $vars = {
	hosts  => [
		{
			name => "[% host.name %]",
		}
	],
};
my $template = Template->new();
$template->process($file, $vars)
    || die "Template process failed: ", $template->error(), "\n" ;

##</code><code>##

<?xml version="1.0" encoding="ISO-8859-1"?>
<workbook>
  <worksheet name="[% config.template %]"><format color="black">
[% FOREACH host IN hosts %]
    <row><bold><format color="white" size="14" bg_color="blue"><cell width="60" text="Configuring de : [% host.name %]" /></format></bold></row>
[% END %]
  </worksheet>
</workbook>

##</code><code>##

<workbook>
  <worksheet name=""><format color="black">

    <row><bold><format color="white" size="14" bg_color="blue"><cell width="60" text="Configuring de : [% host.name %]" /></format></bold></row>

  </worksheet>
</workbook>