I'm not here to write programs for you. Check out this for help in working with references.

$VAR1 = {
          'name' => 'Constants',
          'attribute' => [
                         {
                           'identifier' => '00',
                           'required' => ' true ',
                           'name' => ' session_id ',
                           'type' => ' string ',
                           'ilog' => {
                                     'visible' => ' false ',
                                     'alternate' => ' session id in st
+ring format '
                                   }
                         },
                         {
                           'identifier' => '01',
                           'required' => ' false ',
                           'type' => ' int ',
                           'name' => ' volume ',
                           'ilog' => {
                                     'alternate' => ' the volume ',
                                     'visible' => ' false '
                                   }
                         }
                       ],
          'properties' => {
                          'visible' => ' false '
                        },
          'serviceKey' => '0',
          'version' => '0',
          'ui-visible' => '0',
          'id' => '0',
          'rateTableName' => ''
        };
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In your program, $Event is a hash reference. The data you want is under the attribute key. So you'd start with $Event->{attribute}. That is an array ref. Each element of that array is ANOTHER hash ref. 'name' and 'required' are keys in that hash.

What I usually do in this situation is run the program in the debugger. Then I can incrementally build the expression that gets to the data I need.

If you're thinking 'wow, this is alot of work', well yeah it is. That's why you should invest the time to learn a real XML module instead of XML::Simple.