use XML::Simple;
my $struct = XMLin( \*DATA );
print XMLout($struct, noattr => 1 );

__DATA__
<myconfig_data name="aaa" >
        <level1 my_att="somestring">
                <value>hello1</value>
        </level1>
        <level2>
                <value other_att="bbb">hello2</value>
        </level2>
        <level3>
                <value>hello3</value>
        </level3>
</myconfig_data>

##</code><code>##

<opt>
  <name>aaa</name>
  <level1>
    <my_att>somestring</my_att>
    <value>hello1</value>
  </level1>
  <level2>
    <name>value</name>
    <content>hello2</content>
    <other_att>bbb</other_att>
  </level2>
  <level3>
    <value>hello3</value>
  </level3>
</opt>

##</code><code>##

use Data::Dumper;

use strict;
use XML::Twig;

my $xml_twig = XML::Twig->new(
        pretty_print => 'indented',
        NoLWP => 1,
        discard_spaces => 1,
);

$xml_twig->parse ( \*DATA ) || die "\nError parsing data $@\n";

my $struct=$xml_twig->simplify( noattr => 1 );

print Dumper($struct);


__DATA__
<myconfig_data name="aaa" >
        <level1 my_att="somestring">
                <value>hello1</value>
        </level1>
        <level2>
                <value other_att="bbb">hello2</value>
        </level2>
        <level3>
                <value>hello3</value>
        </level3>
</myconfig_data>

##</code><code>##

$VAR1 = {
          'level1' => {
                        'value' => 'hello1'
                      },
          'level2' => {
                        'value' => 'hello2'
                      },
          'level3' => {
                        'value' => 'hello3'
                      }
        };