My problem is that with the current code, (the one that displayed above) I get this output

<Parameters>
    <ParameterGroupID>1</ParameterGroupID>
  </Parameters>
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But i need it like this format

<Parameters>
<ParameterGroup ID="Group1">
  <Parameter key="Key1">Some Value</Parameter> 
  <Parameter key="Key2">Some Value</Parameter> 
  <Parameter key="Key3">Some Value</Parameter> 
  </ParameterGroup>
<ParameterGroup ID="Group2">
  <Parameter key="Key1">Some Value</Parameter> 
  <Parameter key="Key2">Some Value</Parameter> 
  <Parameter key="Key3">Some Value</Parameter> 
  </ParameterGroup>
  </Parameters>
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The code by using XML::Simple is something like this..

my $xml = { ParameterGroup => [
    {
        ID => 'Group1',
        Parameter => {
            Key1 => {content => 'Some Value'},
            Key2 => {content => 'Some Value'},
            Key3 => {content => 'Some Value'},
        },
    },
    {
        ID => 'Group1',
        Parameter => {
            Key1 => {content => 'Some Value'},
            Key2 => {content => 'Some Value'},
            Key3 => {content => 'Some Value'},
        },
    },
]};

print XMLout($xml,
    RootName => 'Parameters',
    KeyAttr => 'key',
);
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But i want to do the same using LibXML. I hopw my question is clear