Thanks poj, that helps. I overlooked the on_action method. Final code looks like this:

my $proxy = 'http://www.dneonline.com/calculator.asmx';
my $ns = 'http://www.tempuri.org/';    
    
$method = SOAP::Data->name('Add')
         ->attr({xmlns => 'http://tempuri.org/'});
    
$client = SOAP::Lite->new()
        ->proxy($proxy)
        ->ns($ns,'tem')
        ->readable(1);   

$client->on_action( sub { join '', @_  } );    

push(@parms, SOAP::Data->name(intA => $x));
push(@parms, SOAP::Data->name(intB => $y));

$response = $client->call($method => @parms)->result;
print "Result is $response \n";
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