Unity Dependency Injection with N-Layer Project

Web/Web Api
-----------
public class SubProjApiProductController : ApiController
    {

        private readonly IWebApiBusinessFactory _webApiBusinessFactory;

        public SubProjApiProductController(IWebApiBusinessFactory webApiBusinessFactory)
        {
            _webApiBusinessFactory = webApiBusinessFactory;
        }


        [Route("api/products")]
        [HttpPost]
        public async Task<IHttpActionResult> GetProducts([FromBody] IDictionary<string, string> data)
        {
            try
            {
                return Ok(await _webApiBusinessFactory.QueryProductService().GetProductsAsync(data).ConfigureAwait(false));
            }
            catch (Exception ex)
            {
                return Content(HttpStatusCode.NotFound, ex.Message);
                //return NotFound();
            }
        }


        [Route("api/addproduct")]
        [HttpPost]
        public async Task<IHttpActionResult> AddProduct([FromBody] Product product)
        {
            try
            {
                await _webApiBusinessFactory.CommandProductService().InsertAsync(product).ConfigureAwait(false);
                return Ok();
            }
            catch (Exception ex)
            {
                return Content(HttpStatusCode.NotFound, ex.Message);
                //return NotFound();
            }
        }

     }

public static class UnityConfig

    {
        public static void RegisterTypes(IUnityContainer container)
        {

            // NOTE: To load from web.config uncomment the line below.
            // Make sure to add a Unity.Configuration to the using statements.
            // container.LoadConfiguration();
            // container.AddNewExtension<BusinessUnityContainerExtension>(); //for non-parameter 
            container.AddExtension(new BusinessUnityContainerExtension(_connectionString, _connectionTimeout));

            //Product Api
            container.RegisterType<SubProjApiProductController>(new InjectionConstructor(new ResolvedParameter<IWebApiBusinessFactory>()));

        }
}

Business Layer
--------------
public class BusinessUnityContainerExtension : UnityContainerExtension
    {
        #region Fields

        private readonly string _connectionString;
        private readonly int? _connectionTimeout;

        #endregion Fields

        public BusinessUnityContainerExtension(string connectionString, int? connectionTimeout)
        {
            _connectionString = connectionString;
            _connectionTimeout = connectionTimeout ?? 0;
        }

        protected override void Initialize()
        {
            Container.RegisterType<IUnitOfWorkFactory, UnitOfWorkFactory>(new HierarchicalLifetimeManager());

            Container.RegisterType<IWebApiBusinessFactory, WebApiBusinessFactory>(new HierarchicalLifetimeManager(), new InjectionConstructor(new ResolvedParameter<IUnitOfWorkFactory>()));


        }

    }