#!perl
use strict;
use Data::Dump 'pp';
my $data = [{ 'DATE' => '2013-04-25',
  'TW'  => '1','REF' => '1234567',
  'ACC' => '33456790' }];
		  
my $more_data = [{'DOC1' => 'EMAIL1','DOC2' => 'EMAIL2'}];
my @keys = keys %{$more_data->[0]};
@{$data->[0]}{@keys} = @{$more_data->[0]}{@keys};
pp @$data;