SOAPFactory omfactory = OMAbstractFactory.getSOAP11Factory();
SOAPEnvelope reqEnv = omfactory.getDefaultEnvelope();
reqEnv.declareNamespace("http://schemas.xmlsoap.org/soap/envelope/", "soapenv");
reqEnv.declareNamespace("http://www.w3.org/2001/XMLSchema", "xsd");
reqEnv.declareNamespace("http://schemas.xmlsoap.org/soap/encoding/", "SOAP-ENC");
reqEnv.declareNamespace("http://soapinterop/", "tns");
reqEnv.declareNamespace("http://soapinterop.org/xsd", "s");
reqEnv.declareNamespace("http://www.w3.org/2001/XMLSchema-instance", "xsi");
OMElement operation = omfactory.createOMElement("echoString", "http://soapinterop/", null);
reqEnv.getBody().addChild(operation);