Programmatically detect whether Amazon buyer has left a review?

Is it possible to programmatically detect whether an Amazon buyer has left a review on a product? I've been digging through the Product Advertising API to no avail.

Solution

you can use retrieving customer reviews portion of the api here: http://docs.aws.amazon.com/AWSECommerceService/latest/DG/EX_RetrievingCustomerReviews.html

Here is an example of the request:

http://webservices.amazon.com/onca/xml?
  Service=AWSECommerceService
  &Operation=ItemLookup
  &ResponseGroup=Reviews
  &IdType=ASIN
  &ItemId=B004HFS6Z0
  &AssociateTag=[Your_Associate_Tag]
  &AWSAccessKeyId=[Your_AWSAccessKeyId]
  &Timestamp=[YYYY-MM-DDThh:mm:ssZ]
  &Signature=[Request_Signature]

and response:

<Item> 
  <ASIN>B004HFS6Z0</ASIN> 
  <CustomerReviews> 
    <IFrameURL> 
      http://www.amazon.com/reviews/iframe? 
        akid=[Your_AWSAccessKeyId] 
        &alinkCode=xm2 
        &asin=B004HFS6Z0
        &atag=[Your_AssociateTag] 
        &exp=2011-06-01T22%3A32%3A53Z
        &v=2
        &sig=pxn6bbln%2B%2FVTPJdj8oCcXvjTHmo3spkUMjbQMPbhCKI%3D 
    </IFrameURL> 
    <HasReviews>true</HasReviews> 
  </CustomerReviews>
</Item>

you could then sort the responses if needed.