$soap_wdsl = 'https://example.com/service/API?wsdl';
$client = new SoapClient( $soap_wdsl ); 
$response = $client->setTransaction( $params ); 

<SOAP-ENV:Envelope
	xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
	xmlns:ns1="http://soap.example.com/">

<SOAP-ENV:Body>
	<ns1:setTransaction>
		<PARAMS HERE>
	</ns1:setTransaction>
</SOAP-ENV:Body>