Hello,
As Amazon WS is not SOAP, there is no WSDL, but I saw that for each service, they provide a XML schema files. So you should be able to use fglwsdl -x command to generate the 4GL variables according to such XML schema, and then via xml.serializer.domtovariable() to deserialize the xml response in the 4GL variable.
Something like following :
$ fglwsdl -x
g-ecx.images-amazon.com/images/G/01/mwsportal/doc/en_US/products/ProductsAPI_Response.xsd -o
ProductsAPI.incGLOBALS "ProductsAPI.inc"
MAIN
DEFINE req com.HTTPRequest
DEFINE resp com.HTTPResponse
DEFINE doc xml.DomDocument
LET req = com.HTTPRequest(url + query parameters)
LET resp = req.getResponse()
LET doc = resp.getXmlResponse()
CALL xml.Serializer.DomToVariable(doc.getDocumentElement, ProductsAPI.Product)
END MAIN
Frank