Q:

Amazon's Marketplace Web Service inventory not appearing in seller central despite submitting OK

I am using Amazon's MWS to submit a product inventory but it doesn't seem to be working despite saying it has.
I use "SubmitFeed" to submit my test feed XML, which I've pasted below;
<?xml version="1.0" encoding="UTF-8 "?>
<AmazonEnvelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:noNamespaceSchemaLocation="amzn-envelope.xsd">
  <Header>
    <DocumentVersion>1.01</DocumentVersion>
    <MerchantIdentifier>A1BJ5TNE5I3MUD</MerchantIdentifier>
  </Header>
  <MessageType>Product</MessageType>
  <PurgeAndReplace>true</PurgeAndReplace>
  <Message>
    <MessageID>1</MessageID>
    <OperationType>Insert</OperationType>
    <Product>
      <SKU>56789</SKU>
      <StandardProductID>
        <Type>ASIN</Type>
        <Value>B0EXAMPLEG</Value>
      </StandardProductID>
      <ProductTaxCode>A_GEN_NOTAX</ProductTaxCode>
      <DescriptionData>
        <Title>Example Product Title</Title>
        <Brand>Example Product Brand</Brand>
        <Description>This is an example product description.</Description>
        <BulletPoint>Example Bullet Point 1</BulletPoint>
        <BulletPoint>Example Bullet Point 2</BulletPoint>
        <MSRP currency="USD">99.99</MSRP>
        <Manufacturer>Example Product Manufacturer</Manufacturer>
        <ItemType>example-item-type</ItemType>
      </DescriptionData>
      <ProductData>
        <Health>
          <ProductType>
            <HealthMisc>
              <Ingredients>Example Ingredients</Ingredients>
              <Directions>Example Directions</Directions>
            </HealthMisc>
          </ProductType>
        </Health>
      </ProductData>
    </Product>
  </Message>
</AmazonEnvelope>

This seems to work OK, it returns the "FeedSubmissionId" etc...
<?xml version="1.0"?>
<SubmitFeedResponse xmlns="http://mws.amazonaws.com/doc/2009-01-01/">
    <SubmitFeedResult>
        <FeedSubmissionInfo>
            <FeedSubmissionId>3008008200</FeedSubmissionId>
            <FeedType>_POST_PRODUCT_DATA_</FeedType>
            <SubmittedDate>2012-03-29T11:12:04+00:00</SubmittedDate>
            <FeedProcessingStatus>_SUBMITTED_</FeedProcessingStatus>
        </FeedSubmissionInfo>
    </SubmitFeedResult>
    <ResponseMetadata>
        <RequestId>9ff22ff1-e86b-45a1-b1ce-4b873f45e90a</RequestId>
    </ResponseMetadata>
</SubmitFeedResponse>

I then check the status of the feed submission using "GetFeedSubmissionList" and it returns "DONE"....
<?xml version="1.0"?>
<GetFeedSubmissionListResponse xmlns="http://mws.amazonaws.com/doc/2009-01-01/">
    <GetFeedSubmissionListResult>
        <NextToken />
        <HasNext>false</HasNext>
        <FeedSubmissionInfo>
            <FeedSubmissionId>3008008200</FeedSubmissionId>
            <FeedType>_POST_PRODUCT_DATA_</FeedType>
            <SubmittedDate>2012-03-29T11:12:04+00:00</SubmittedDate>
            <FeedProcessingStatus>_DONE_</FeedProcessingStatus>
            <StartedProcessingDate>2012-03-29T11:12:13+00:00</StartedProcessingDate>
            <CompletedProcessingDate>2012-03-29T11:12:33+00:00</CompletedProcessingDate>
        </FeedSubmissionInfo>
    </GetFeedSubmissionListResult>
    <ResponseMetadata>
        <RequestId>4afd9b3d-33c6-4c15-bbe1-51304dc1cd24</RequestId>
    </ResponseMetadata>
</GetFeedSubmissionListResponse>

But when I login to sellers central and check out the inventory, the test product isn't there.  I can't seem to find it anywhere - so where exactly is it submitting to?  I've definitely not got any of the merchant id's mixed up - because I'm doing it all through the same account, authorising the developer account to use the seller account etc.
Is there something I'm not doing correctly?  Do I need to do call another function to commit the data or something?
It's really frustrating because Amazon's documentation sucks so bad.  I've actually come this far thanks to Stackoverflow and random blog posts out there.

A:

You do need to change a few things within this feed but it's just a starting point.
First ....
<PurgeAndReplace>false</PurgeAndReplace> // unless you want to delete all other inventory
  <Message>
    <MessageID>1</MessageID>
    <OperationType>Update</OperationType> //instead of insert

Next ... only use this next section if you know the exact ASIN you want to map the SKU to.
<StandardProductID>
   <Type>ASIN</Type>
   <Value>B0EXAMPLEG</Value>
</StandardProductID>

Then ... verify that the upload was successful. 'DONE' is not the same thing. You need to do a GetFeedSubmissionResult, which is a file download, and check the contents for 
<ProcessingSummary>
    <MessagesProcessed>1</MessagesProcessed>
    <MessagesSuccessful>1</MessagesSuccessful>
    <MessagesWithError>0</MessagesWithError>
    <MessagesWithWarning>0</MessagesWithWarning>
</ProcessingSummary>

AND MOST IMPORTANTLY ...... Unlike doing a flat file upload when using the XML and doing just the Product Feed it does not create a listing.
You must also do an Inventory (with quantity) and a Price Feed in order to create an Offer Listing viewable through your seller central page.

