Knockoutjs observableArray with null properties in array items

gistfile1.txt

<table>
	<thead>
		<tr>
			<th>Name</th>
			<th>Something that could be NULL</th>
		</tr>
	</thead>
	<tbody data-bind="foreach: valuesArray">
		<tr>
			<td data-bind="text: Name"></td>
			<td data-bind="safeText: Nullable"></td>
		</tr>
	</tbody>
</table>

<script type="text/javascript">

	ko.bindingHandlers.safeText = {
		update: function (element, valueAccessor, allBindingsAccessor) {
			var text;
			try {
				text = ko.utils.unwrapObservable(valueAccessor());
			} catch (e) {
				text = "";
			} 
			ko.bindingHandlers.text.update(element, function () { return text; });
		}
	};

	var viewModel = {
		valuesArray : ko.observableArray([])
	};

	ko.applyBindings(viewModel);

	viewModel.valuesArray.push({Name: "no null value", Nullable: "NOT NULL"});
	viewModel.valuesArray.push({Name: "has a null value"});
</script>