Привязка данных Knockout validatedObservable не работает должным образом

Я пытаюсь привязать данные к validatedObservable, но элемент управления не выглядит обновляемым, как другие наблюдаемые нокауты.

Поиграйте здесь, http://jsfiddle.net/EricHerlitz/x7UUg/

Краткое объяснение

// variable with the data bound observable
that.validationErrors = ko.validatedObservable();

// Elements to validate
var validationGroup = {
    email1: that.email1,
    firstName: that.firstName
};

// Trying to use the validatedObservable in a normal knockout way doesn't work
that.validationErrors(validationGroup);

// This will fill the variable with the observable result but as usual when performing this pattern the viewmodel must be rebound.
that.validationErrors = ko.validatedObservable(validationGroup);

Источник

<h3>Registrering</h3>
<div class="form-group">
    <label for="Email1">E-postadress</label>
    <input data-bind="value: email1" id="Email1" class="form-control" placeholder="E-postadress (du kommer få lösenords-länk skickad hit)" />
</div>
<div class="form-group">
    <label for="Firstname">Förnamn</label>
    <input data-bind="value: firstName" id="Firstname" class="form-control" placeholder="Förnamn" />
</div>

<button type="button" class="btn btn-primary" data-bind="click: registerClick">Registrera</button>

<div class="alert alert-danger" data-bind="visible: !validationErrors.isValid()">
    <button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button>
    <h4>There be dragons!</h4>
    <div data-bind="foreach: validationErrors.errors">
        <div data-bind="text: $data"></div>
    </div>
</div>

Js

var GK = GK || {};
GK.VM = GK.VM || {};

GK.VM.Member = function (template) {
    /*** Private variables ***/
    var that = this;

    /*** Public variables ***/
    that.validationErrors = ko.validatedObservable();

    // variables with validation, https://github.com/Knockout-Contrib/Knockout-Validation
    that.email1 = ko.observable().extend({
        required: { params: true, message: "missingEmail" },
        pattern: { params: /^([\d\w-\.]+@([\d\w-]+\.)+[\w]{2,4})?$/, message: "wrongEmailFormat" }
    });
    that.firstName = ko.observable().extend({
        required: { params: true, message: "missingFirstName" }
    });

    that.registerClick = function () {

        // Elements to validate
        var validationGroup = {
            email1: that.email1,
            firstName: that.firstName
        };

        // This would be ideal but doesn't work
        //that.validationErrors(validationGroup);
        //console.log(that.validationErrors.errors()); // does not contain any erros

        // This will destroy the data-bind but register the validatedObservable
        // Requires rebinding of the control :(
        that.validationErrors = ko.validatedObservable(validationGroup);
        console.log(that.validationErrors.errors()); // contains errors
    };
};

var viewModel = new GK.VM.Member();
ko.applyBindings(viewModel);

Любые советы, как справиться с этим? Спасибо.