foreach my $key1 (sort keys %somehash) {
   foreach my $key2 (sort keys %{$somehash{$key1}}) {
      foreach my $key3 (sort keys %{$somehash{$key1}{$key2}}) {
         print($key1, ':', $somehash{$key1}{$key2}{$key3}, "\n");
      }
   }
}
[download]

or

foreach my $key1 (sort keys %somehash) {
   my $key2 = 'justtest';
   foreach my $key3 (sort keys %{$somehash{$key1}{$key2}}) {
      print($key1, ':', $somehash{$key1}{$key2}{$key3}, "\n");
   }
}
[download]

or

foreach my $key1 (sort keys %somehash) {
   foreach my $key2 (sort keys %{$somehash{$key1}{justtest}}) {
      print($key1, ':', $somehash{$key1}{justtest}{$key2}, "\n");
   }
}
[download]