Acknowledge Alert via SDK Perl

I am calling the Acknowledge Alert syntax using the example from the sample.pl file for the Perl example.

When I do the following

      my $alertDefId = $alert->{alertdefid};

       my $alertNodeId = $alert->{activeobject};

       my $node_alerts = \SOAP::Data->name('ArrayOfAlertInfo')->value(

                      SOAP::Data->name('AlertInfo')->attr({xmlns=>'http://schemas.solarwinds.com/2008/Orion'})->value(

                      SOAP::Data->name('DefinitionId')->type('')->value($alertDefId),

                      SOAP::Data->name('ObjectType')->type('')->value('Node'),

                      SOAP::Data->name('ObjectId')->type('')->value($alertNodeId)

                     )

                   );

       my $result = $swql->swis->Invoke( 'Orion.AlertStatus', 'Acknowledge', [$node_alerts] );

I get a return value of 'false' and the Alert is NOT Acknowledged. 

How can I acknowledge the Alert through the SDK, remember I am doing this with PERL and I am using the InformationService.pm and Orion.pm modules?

Thank you,

Charles