Update rally's task revision
===

could someone give me an example on how to update a task's revision using javascript?

I just created a task with

    rallyDataSource.create("task", {"Name": "DEV: Do Work", "WorkProduct": thisDefect}, onCreateComplete,onCreateError);

Now I want to update description of the first revision of the task from "Original revision" to "Auto-created task". I tried to get _ref of that first revision, but don't know how. Using 

    function onCreateComplete(object, warnings) {
        var createdObject = object;
        rallyDataSource.update({"_ref": createdObject.RevisionHistory.Revisions[0]._ref, "Description": "Auto-created task"}, onComplete,onError);
    }

does not work

Thanks

