Product.Config.prototype.updateProductShortDescription = function(productId) {
    var shortDescription = this.config.shortDescription;
    if (productId && this.config.childProducts[productId].shortDescription) {
        shortDescription = this.config.childProducts[productId].shortDescription;
    }
    $$('#product_addtocart_form div.short-description div.std').each(function(el) {
        el.innerHTML = shortDescription;
    });
};