Disable option caption with knockout

Supposed to disable the first "caption" select option using a re-usable bindingHandler

HTML

<label>First Go
    <select data-bind="options: items, optionsCaption:'please select', optionsAfterRender: function(option, item) { ko.applyBindingsToNode(option, {disable: !item}, item); }"></select>
</label>

JavaScript

var viewModel = {

    items: ko.observableArray(['one', 'two'])
};

ko.bindingHandlers.disableOptionsCaption = {
    init: function (element) {

        ko.applyBindingsToNode(element, {
            optionsAfterRender: function (option, item) {

                ko.applyBindingsToNode(option, {
                    disable: !item
                }, item);

            }
        });

    }
};


ko.applyBindings(viewModel);