Suitecrm API function default value not working

Hi All,

I am working on creating a new endpoint and in the registry.php file for v4_1, I register new endpoint ike this -

$this->serviceClass->registerFunction(
            'my_call_request', 
            array('session'=>'xsd:string', 'case_id'=>'xsd:string', 'my_calls_requested' => 'xsd:boolean'),
            array('return'=>'xsd:boolean'));

and in the service\v4_1\SugarWebServiceImplv4_1.php file I wrote function like this-

public function my_call_request($session, $case_id, $my_calls_requested= 0) {
// code
}

when this endpoint executes without 3rd paramter value, I am assuning default value 0 should be assigned to $my_calls_requested variable which is 0 but instead null is assigned to it.

Is there any solution on it, sot that 0 should get assigned to it?