You can use KeyAttr=>{Item1=>'name'}

use XML::Simple;
use Data::Dumper;
my $hash= {
 'root' => {
   'item1' => {
      'item1a' => 'n1', 'item1b'=>'jh'
   }
  }
};
my $xs = new XML::Simple( );
my $xml = $xs->XMLout($hash, NoAttr => 1, RootName=>undef, KeyAttr=>{I
+tem1=>'name'} );
print Dumper $xml;
[download]

Or you do what haukex said