Amazon API身份验证错误

试图使用AmazonAPI获取产品数据,但目前失败得很惨。

获取以下错误:(客户端身份验证方案“匿名”禁止HTTP请求。)

有人愿意为我指明正确的方向,或者提供一个指向API使用的好例子的链接吗?

Dim itemRequest As New ItemSearchRequest

With itemRequest
    .Keywords = "Matrix"
    .SearchIndex = "DVD"
    .ResponseGroup = New String() {"Images"}
End With

Dim request As New ItemSearch
request.AWSAccessKeyId = _AWSAccessKeyId
request.Request = New ItemSearchRequest() {itemRequest}

Dim binding As New BasicHttpBinding(BasicHttpSecurityMode.Transport)
binding.MaxReceivedMessageSize = Integer.MaxValue

Dim serviceProvider As New AWS_Services.AWSECommerceServicePortTypeClient(binding, New EndpointAddress("https://webservices.amazon.com/onca/soap?Service=AWSECommerceService"))


serviceProvider.ChannelFactory.Endpoint.Behaviors.Add(New AmazonSigningEndpointBehavior(_AssociateTag, _AWSAccessKeyId))

Dim response As ItemSearchResponse = serviceProvider.ItemSearch(request)