Yes, that is the code we are using (see below)...
' Get the shopping cart
Dim cart As ShoppingCartInfo = ECommerceContext.CurrentShoppingCart
' Set the shopping cart
ShoppingCartInfoProvider.SetShoppingCartInfo(cart)
cart.SetValue("ArtClubCode", "12345")
Dim strArtClubCode As String = cart.GetValue("ArtClubCode")