my %file_attachments = (
             '103496-1'  => { 'CLVD' => '5678', 'COMP' => '1234', 'FD' => '0010', 'File' => 'text.txt'},
                       );

print Dumper(%file_attachments);
print "\n";

my %newfile_attachments;
my $fn;

my %newfile_attachments;
foreach $fn (keys %file_attachments) {
  $newfile_attachments{$fn->{FirstNum}}= $fn;
  delete $fn->{FirstNum};
}



print Dumper(%newfile_attachments);
print "\n";