print "@field \n";
#                ^
[download]

#!/usr/bin/perl
use strict;
use warnings;
use XML::Twig;
my $xml = 'value.xml';
my $twig = new XML::Twig(
  twig_handlers =>{ field => \&field }
);
$twig->parsefile($xml);

sub field {
  my ($t,$e) = @_;
  for ($e->children){
    if ($_->gi eq 'key'){
      print $_->att('name')." ";
    } elsif ($_->gi eq 'value'){      
      print $_->att('id')."\n";
    }
  }
}
[download]

This, considering the following from XML::Simple's documentation (emphasis mine):

STATUS OF THIS MODULE ^

The use of this module in new code is discouraged. Other modules are available which provide more straightforward and consistent interfaces. In particular, XML::LibXML is highly recommended.

The major problems with this module are the large number of options and the arbitrary ways in which these options interact - often with unexpected results.

Patches with bug fixes and documentation fixes are welcome, but new features are unlikely to be added.