Hi I'm trying to create a custom shipping method as it describes on this page:
http://www.publicvoid.dk/BuildingACustomShippingMethodService.aspx

Unfortunately it won't let me build the project because:

'System.Collections.Generic.ICollection<UCommerce.EntitiesV2.OrderLine>' does not contain a definition for 'PurchaseOrders' ...

'UCommerce.EntitiesV2.Shipment' does not contain a definition for 'ShippingMethods' ...

'UCommerce.EntitiesV2.Shipment' does not contain a definition for 'OrderAddresses' ...

'UCommerce.EntitiesV2.Shipment' does not contain a definition for 'ShippingMethods' ...

using System;
using System.Linq;
using UCommerce;
using UCommerce.EntitiesV2;
using UCommerce.Transactions.Shipping;

namespace AirAmbulanceCustomShippingService
{
    public class AirAmbulanceCustomShippingService : IShippingMethodService
    {
        public string Name { get; set; }

        public Money CalculateShippingPrice(Shipment shipment)
        {
            var numberOfItems = shipment.OrderLines.Count();
            decimal shippingPrice = 0;
            switch (numberOfItems)
            {
                case 1:
                    shippingPrice = 150;
                    break;
                case 2:
                    shippingPrice = 250;
                    break;
                case 3:
                    shippingPrice = 350;
                    break;
                default:
                    shippingPrice = 450;
                    break;
            }
            return new Money(shippingPrice, shipment.OrderLines.PurchaseOrders.Single().Currencies.Single());
        }

        public bool ValidateForShipping(Shipment shipment)
        {
            if (shipment.ShipmentAddressId <= 0)
                throw new InvalidOperationException("Cannot validate shipment for country. Remember to set the shipping address for shipment.");
            var shippingMethod = shipment.ShippingMethods.SingleOrDefault();
            if (shippingMethod == null)
                throw new InvalidOperationException("Cannot validate destination country for shipment. It does not contain a shipping method. Remember to add a shipping method to your shipment before validating.");
            return ValidateShippingDestination(shipment.OrderAddresses.Single(), shipment.ShippingMethods.Single());
        }

        /// <summary>
        /// Validates the order lines according to their desired destination and configured contries for shipping method
        /// </summary>
        /// <returns></returns>
        protected virtual bool ValidateShippingDestination(OrderAddress shippingAddress, ShippingMethod shippingMethod)
        {
            var eligibleCountries = shippingMethod.EligibleCountries;
            if (eligibleCountries == null) return false;
            return eligibleCountries.SingleOrDefault(x => x.CountryId == shippingAddress.CountryId) != null;
        }        
    }
}