Sitecore Commerce - Extend Create User Pipeline

var customerService = new CustomerServiceProvider();
var request = new CreateUserRequest("JohnSmith", "password", "john@abczyx.net", "webstore");
var result = customerService.CreateUser(request);

 request.Properties.Add(new PropertyItem("JoinNewsletter", true));

public class CustomCreateUser : Sitecore.Commerce.Engine.Connect.Pipelines.Customers.CreateUser
{
    public CustomCreateUser(IEntityFactory entityFactory) : base(entityFactory)
    {
    }

    public override void Process(ServicePipelineArgs args)
    {
        CreateUserRequest request;
        CreateUserResult result;
        ValidateArguments<CreateUserRequest, CreateUserResult>(args, out request, out result);
        Sitecore.Diagnostics.Assert.IsNotNull((object)request.UserName, "request.UserName");
        Sitecore.Diagnostics.Assert.IsNotNull((object)request.Password, "request.Password");
        Container container = this.GetContainer(request.Shop.Name, string.Empty, currency: args.Request.CurrencyCode);
        CommerceUser commerceUser1 = result.CommerceUser;
        if (commerceUser1 != null && commerceUser1.UserName.Equals(request.UserName, StringComparison.OrdinalIgnoreCase))
        {
            string entityId = "Entity-Customer-" + request.UserName;
            ServiceProviderResult currentResult = new ServiceProviderResult();
            EntityView entityView = this.GetEntityView(container, entityId, string.Empty, "Details", string.Empty, currentResult);
            if (currentResult.Success && !string.IsNullOrEmpty(entityView.EntityId))
            {
                base.Process(args);
                return;
            }
        }
        EntityView entityView1 = this.GetEntityView(container, string.Empty, string.Empty, "Details", "AddCustomer", (ServiceProviderResult)result);
        if (!result.Success)
            return;
        entityView1.Properties.FirstOrDefault<ViewProperty>((Func<ViewProperty, bool>)(p => p.Name.Equals("Domain", StringComparison.OrdinalIgnoreCase))).Value = request.UserName.Split('\\')[0];
        entityView1.Properties.FirstOrDefault<ViewProperty>((Func<ViewProperty, bool>)(p => p.Name.Equals("LoginName", StringComparison.OrdinalIgnoreCase))).Value = request.UserName.Split('\\')[1];
        entityView1.Properties.FirstOrDefault<ViewProperty>((Func<ViewProperty, bool>)(p => p.Name.Equals("AccountStatus", StringComparison.OrdinalIgnoreCase))).Value = "ActiveAccount";
        if (!string.IsNullOrEmpty(request.Email))
            entityView1.Properties.FirstOrDefault<ViewProperty>((Func<ViewProperty, bool>)(p => p.Name.Equals("Email", StringComparison.OrdinalIgnoreCase))).Value = request.Email;
        //new custom code for getting data to commerce pipeline
        entityView1.Properties.Add(new ViewProperty
        {
            Name = "JoinNewsletter",
            Value = request.Properties["JoinNewsletter"].ToString(),
            UiType = "string",
            IsHidden = true,
            IsReadOnly = true
        });
        //end of a new code
        CommerceCommand commerceCommand = this.DoAction(container, entityView1, (ServiceProviderResult)result);
        if (commerceCommand != null && commerceCommand.ResponseCode.Equals("ok", StringComparison.OrdinalIgnoreCase))
        {
            //modification here, we couldn't use entityFactory
            CommerceUser commerceUser2 = new CommerceUser();
            commerceUser2.Email = request.Email;
            commerceUser2.UserName = request.UserName;
            commerceUser2.ExternalId = commerceCommand.Models.OfType<CustomerAdded>().FirstOrDefault<CustomerAdded>().CustomerId;
            result.CommerceUser = commerceUser2;
            request.Properties.Add(new PropertyItem()
            {
                Key = "UserId",
                Value = (object)result.CommerceUser.ExternalId
            });
        }
        base.Process(args);
    }
    // had to copy method from dll because there is internal
    private  static void ValidateArguments<TRequest, TResult>(
        ServicePipelineArgs args,
        out TRequest request,
        out TResult result)
        where TRequest : ServiceProviderRequest
        where TResult : ServiceProviderResult
    {
        Sitecore.Diagnostics.Assert.ArgumentNotNull((object)args, nameof(args));
        Sitecore.Diagnostics.Assert.ArgumentNotNull((object)args.Request, "args.Request");
        Sitecore.Diagnostics.Assert.ArgumentNotNull((object)args.Request.RequestContext, "args.Request.RequestContext");
        Sitecore.Diagnostics.Assert.ArgumentNotNull((object)args.Result, "args.Result");
        request = args.Request as TRequest;
        result = args.Result as TResult;
        Sitecore.Diagnostics.Assert.IsNotNull((object)request, "The parameter args.Request was not of the expected type.  Expected {0}.  Actual {1}.", typeof(TRequest).Name, args.Request.GetType().Name);
        Sitecore.Diagnostics.Assert.IsNotNull((object)result, "The parameter args.Result was not of the expected type.  Expected {0}.  Actual {1}.", typeof(TResult).Name, args.Result.GetType().Name);
    }
}

<commerce.customers.createUser>
        <processor type="Sitecore.Commerce.Pipelines.Customers.CreateUser.CreateUserInExternalSystem, Sitecore.Commerce.Connect.Core">
          <patch:delete/>
        </processor>
        //deleted code
        //<processor patch:before="processor[@type='Sitecore.Commerce.Pipelines.Customers.CreateUser.CreateUserInSitecore, Sitecore.Commerce.Connect.Core']" type="Sitecore.Commerce.Engine.Connect.Pipelines.Customers.CreateUser, Sitecore.Commerce.Engine.Connect">
        //added code
        <processor patch:before="processor[@type='Sitecore.Commerce.Pipelines.Customers.CreateUser.CreateUserInSitecore, Sitecore.Commerce.Connect.Core']" 
        type="NameOfAProject.Foundation.Commerce.Pipelines.Customer.CustomCreateUser, NameOfAProject.Foundation.Commerce">
          <param ref="entityFactory" />
        </processor>
      </commerce.customers.createUser>

.ConfigurePipeline<IDoActionPipeline>(configure
                {
                    configure.Replace<DoActionAddCustomerBlock, CustomDoActionAddCustomerBlock>();
                })

public class CustomDoActionAddCustomerBlock: DoActionAddCustomerBlock
    {
        private readonly ITranslateEntityViewToCustomerPipeline _translatePipeline;
        private readonly CreateCustomerCommand _createCustomerCommand;

        public CustomDoActionAddCustomerBlock(CreateCustomerCommand createCustomerCommand,
            ITranslateEntityViewToCustomerPipeline translatePipeline) : base(createCustomerCommand, translatePipeline)
        {
            _createCustomerCommand = createCustomerCommand;
            _translatePipeline = translatePipeline;
        }

        public override async Task<EntityView> Run(
      EntityView arg,
      CommercePipelineExecutionContext context)
        {
            if (string.IsNullOrEmpty(arg?.Action) || !arg.Action.Equals(context.GetPolicy<KnownCustomerActionsPolicy>().AddCustomer, StringComparison.OrdinalIgnoreCase))
                return arg;
            CustomerPropertiesPolicy propertiesPolicy = context.GetPolicy<CustomerPropertiesPolicy>();
            ViewProperty viewProperty1 = arg.Properties.FirstOrDefault<ViewProperty>((Func<ViewProperty, bool>)(p => p.Name.Equals(propertiesPolicy?.Domain, StringComparison.OrdinalIgnoreCase)));
            if (string.IsNullOrEmpty(viewProperty1?.Value) || !propertiesPolicy.Domains.Contains(viewProperty1?.Value))
            {
                string str1 = viewProperty1 == null ? propertiesPolicy?.Domain : viewProperty1.DisplayName;
                string str2 = await context.CommerceContext.AddMessage(context.GetPolicy<KnownResultCodes>().ValidationError, "InvalidOrMissingPropertyValue", new object[1]
                {
          (object) str1
                }, "Invalid or missing value for property '" + propertiesPolicy?.Domain + "'.").ConfigureAwait(false);
                return arg;
            }
            ViewProperty viewProperty2 = arg.Properties.FirstOrDefault<ViewProperty>((Func<ViewProperty, bool>)(p => p.Name.Equals(propertiesPolicy?.LoginName, StringComparison.OrdinalIgnoreCase)));
            if (string.IsNullOrEmpty(viewProperty2?.Value))
            {
                string str3 = viewProperty2 == null ? propertiesPolicy?.LoginName : viewProperty2.DisplayName;
                string str4 = await context.CommerceContext.AddMessage(context.GetPolicy<KnownResultCodes>().ValidationError, "InvalidOrMissingPropertyValue", new object[1]
                {
          (object) str3
                }, "Invalid or missing value for property '" + propertiesPolicy?.LoginName + "'.").ConfigureAwait(false);
                return arg;
            }

            //mew code
            var joinNewsletterComponent = new JoinNewsletterComponent
            {
                JoinNewsletter = bool.Parse(arg.Properties
                    .FirstOrDefault(p => p.Name.Equals("JoinNewsletter", StringComparison.OrdinalIgnoreCase))?.Value)
            };
            context.CommerceContext.AddObject(joinNewsletterComponent);
            //end of new code
            Customer customer1 = await this._translatePipeline.Run(arg, context).ConfigureAwait(false);
            Customer customer2 = await this._createCustomerCommand.Process(context.CommerceContext, customer1).ConfigureAwait(false);
            return arg;
        }
    }

 public class JoinNewsletterComponent : Component
   {
       public JoinNewsletterComponent()
       {
           Name = "JoinNewsletterComponent";
       }
       public bool JoinNewsletter { get; set; } 

.ConfigurePipeline<ICreateCustomerPipeline>(c =>
               {
                   c.Add<AddJoinNewsletterBlock>().After<CreateCustomerBlock>();
               })

public class AddJoinNewsletterBlock : PipelineBlock<Customer, Customer, CommercePipelineExecutionContext>
  {
      public override Task<Customer> Run(Customer customer, CommercePipelineExecutionContext context)
      {
          Condition.Requires(customer).IsNotNull("The customer can not be null");
          var joinNewsLetter = false;
          var joinNewsletterComponent= context.CommerceContext.GetObject<JoinNewsletterComponent>();
          if (joinNewsletterComponent != null) joinNewsLetter = joinNewsletterComponent.JoinNewsletter;
          customer.GetComponent<JoinNewsletterComponent>().JoinNewsletter = joinNewsLetter;
          return Task.FromResult(customer);
      }
  }