AndroidにおけるSOAPのanytype問題

SoapObject resultObj = null;
		try{
			SoapObject rpc = new SoapObject(NAMESPACE, METHORD_NAME); 
	    	
	    	SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); 
	    	envelope.bodyOut = rpc; 
	    	envelope.setOutputSoapObject(rpc);
	    	
	    	rpc.addProperty("methodName", methodName);
	    	rpc.addProperty("xmlInfo", xml_info);
	    	
	    	String URL = SysConfig.getInstance().getRootPath()+"services/"+AXIS_NAME+"?wsdl"; 
	    	HttpTransportSE ht = new HttpTransportSE(URL); 
	    	ht.debug = true;
	    	
	    	String SOAP_ACTION = NAMESPACE+"/" + METHORD_NAME; 
	    	ht.call(SOAP_ACTION, envelope);  
	    	
	    	resultObj = (SoapObject)envelope.bodyIn;
		}catch(Throwable ex){
			Log.d("connect",ex.getMessage());
			resultObj = new SoapObject(NAMESPACE, METHORD_NAME);
			resultObj.addProperty("return", "      ");
		}

測定時に、

String rtnStr = resultObj.getProperty("return").toString();

方式で取得したrtnStrはanyType{}であり,しばらくの間調べ検証した結果,サーバがreturn「」を返すと,このような状況になることが分かった.