Using vimPort to createTask failed , reporting task type not correct.

Hi,

Im trying to use VimPortType 's createTask function to create a custome task. the calling is like:

taskInfo = _vimPort.createTask(taskManagerMoref, hostMoref, taskId,null, false, null, null);

the taskManagerMoref is Mof of TaskManager,  taskId is a string , why it throw this taskType not correct exception? is there any restriction of the taskId? thanks.

[2018-05-18T02:37:30.135Z] [ERROR] http-bio-5090-exec-7          com.huawei.esdk.storage.model.task.TaskProcessor                  com.sun.xml.internal.ws.fault.ServerSOAPFaultException: Client received SOAP Fault from server: A specified parameter was not correct: taskType Please see the server log to find more detail regarding exact cause of the failure.
        at com.sun.xml.internal.ws.fault.SOAP11Fault.getProtocolException(SOAP11Fault.java:178)
        at com.sun.xml.internal.ws.fault.SOAPFaultBuilder.createException(SOAPFaultBuilder.java:124)
        at com.sun.xml.internal.ws.client.sei.StubHandler.readResponse(StubHandler.java:238)
        at com.sun.xml.internal.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:189)
        at com.sun.xml.internal.ws.db.DatabindingImpl.deserializeResponse(DatabindingImpl.java:276)
        at com.sun.xml.internal.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:104)
        at com.sun.xml.internal.ws.client.sei.SyncMethodHandler.invoke(SyncMethodHandler.java:77)
        at com.sun.xml.internal.ws.client.sei.SEIStub.invoke(SEIStub.java:147)
        at com.sun.proxy.$Proxy701.createTask(Unknown Source)