my @sorted =
   map substr($_, 8),
   sort
   map join('', (/(..)-(..)-(....)/)[2,1,0], $_),
   @dates;  # DD-MM-YYYY

##</code><code>##

#!/usr/bin/perl --
use strict;
use warnings;
use Data::Dumper;
my @dates = qw[
    08-15-2011
    08-10-2011
    08-05-2011
];

print "\ndates ", Dumper( \@dates );

#~ my @firstTransform =  map join('', (/(..)-(..)-(....)/)[2,1,0], $_), @dates;  # DD-MM-YYYY
my @firstTransform =  map join('', ReorderForCmp($_), $_), @dates;  # DD-MM-YYYY
print "\nfirstTransform ", Dumper( \@firstTransform  );

my @firstSorted = sort @firstTransform  ;
print "\nfirsSorted ", Dumper( \@firstSorted  );

my @finalTransform = map substr($_, 8), @firstSorted ;
print "\nfinalTransform ", Dumper( \@finalTransform );

sub ReorderForCmp {
    my( $one ) = @_;
    my @date = $one =~ /(..)-(..)-(....)/;

#~     return @date[2,1,0];
    return $date[2], $date[1], $date[0];
}

__END__

##</code><code>##

dates $VAR1 = [
          '08-15-2011',
          '08-10-2011',
          '08-05-2011'
        ];

firstTransform $VAR1 = [
          '2011150808-15-2011',
          '2011100808-10-2011',
          '2011050808-05-2011'
        ];

firsSorted $VAR1 = [
          '2011050808-05-2011',
          '2011100808-10-2011',
          '2011150808-15-2011'
        ];

finalTransform $VAR1 = [
          '08-05-2011',
          '08-10-2011',
          '08-15-2011'
        ];