nicolas told once: "that when a product has a custom item field that is required and that you configure the listing to not display the custom item fields on the listing but to display the add to cart buttons, then the system is supposed to display a "choose options" button instead of the add to cart button." Its not working for me.:
When i set Custom item fields to Yes, then "choose options" button is ok on some products, but for others these fields are displaying in Products listing, which is not ok for me.