code: public void setSoapActionOnApiVersion(String apiVersion) {
          log.trace("API Version detected: " + apiVersion);
          if ("4.0".equals(apiVersion)) {
              soapAction = SoapAction.SOAP_ACTION_V40.toString();
          }
          else if ("4.1".equals(apiVersion)) {
              soapAction = SoapAction.SOAP_ACTION_V41.toString();
          }
          else if ("5.0".equals(apiVersion)) {
              soapAction = SoapAction.SOAP_ACTION_V50.toString();
          }
          else if ("5.1".equals(apiVersion)) {
              soapAction = SoapAction.SOAP_ACTION_V51.toString();
          }
          else if ("5.5".equals(apiVersion)) {
              soapAction = SoapAction.SOAP_ACTION_V55.toString();
          }
          else if ("6.0".equals(apiVersion)) {
              soapAction = SoapAction.SOAP_ACTION_V60.toString();
          }
          else { //always defaults to latest version
              soapAction = SoapAction.SOAP_ACTION_V60.toString();
          }
          log.trace("Set soapAction to: " + soapAction);
      }
docs: /*===============================================
  API versions *
  "2.0.0"    VI 3.0
  "2.5.0"    VI 3.5 (and u1)
  "2.5u2"   VI 3.5u2 (and u3, u4)
  "4.0"       vSphere 4.0 (and u1)
  "4.1"       vSphere 4.1
  "5.0"       vSphere 5.0
  "5.1"       vSphere 5.1
  ===============================================