The previous version of this Gist wasn't up to date anymore with the latest version of autoNumeric (1.9.17). Not saying this works perfectly, but first tests show that it does work.

knockout.autonumeric.js

ko.bindingHandlers.autoNumeric =  {
    init: function (el, valueAccessor, bindingsAccessor, viewModel) {
        var $el = $(el),
            bindings = bindingsAccessor(),
            settings = bindings.settings,
            value = valueAccessor();

        $el.autoNumeric(settings);
        $el.autoNumeric('set', parseFloat(ko.utils.unwrapObservable(value()), 10));
        $el.change(function() {
            value(parseFloat($el.autoNumeric('get'), 10));
        });
    },
    update: function (el, valueAccessor, bindingsAccessor, viewModel) {
        var $el = $(el),
            newValue = parseFloat(ko.utils.unwrapObservable(valueAccessor()), 10),
            elementValue = parseFloat($el.autoNumeric('get'), 10),
            valueHasChanged = (newValue != elementValue);

        if ((newValue === 0) && (elementValue !== 0) && (elementValue !== "0")) {
            valueHasChanged = true;
        }

        if (valueHasChanged) {
            $el.autoNumeric('set', newValue);
            setTimeout(function () { $el.change() }, 0);
        }
    }
};

Usage (often forgotten, isn't it?):

<input type="text" data-bind="
    autoNumeric: observablePropertyToBindTo, 
    settings: { vMin: 0, vMax: 40 }" />

This is just a simple rewrite of the code. I don't like the fact that 2 bindings are needed (one for data and one for settings). Ideally you would combine it to something like:

<input type="text" data-bind="
    autoNumeric: {
        data: observablePropertyToBindTo, 
        settings: { vMin: 0, vMax: 40 }
    }" />

Very useful!