Add via ajax to the cart the product to the product through the collection, add a property.
Before saving and after this property shows.
But when I turn on the shopping cart page, a property generally there, in what the reason can not understand.
P. S. This property is located in the product information block, if that.
P. S. S. Working on the link
, cart and add to cart custom functionality (without using standard components from Bitrix).