Extreme performance degradation for lengthy XML Responses

I have migrated my existing web services from Sneak Preview 2.0.0 on WebAS6.3 to Final Release 2.0.4 of Netweaver Developer Studio on WebAS 6.4.

The rendering of XML responses from the Web Services in the older Version was significantly faster and things worked well with respect to the response time and length of the XML Response packets.

However i am surprised to find that the new Version is not only much slower(long response times) but also fails in Serialization/Deserialization while sending lenghty XML Response packets back from the J2EE Engine to the WebDynpro Runtime. Following is the summary of the error i get in my application for requests yielding lenghty XML responses from the Web Services.

Service Call Exception; nested exception is: com.sap.engine.service.webservices.jaxrpc.exceptions.XmlUnmarshalException: XML Deserialization Error.

Please note that this application works perfectly well for smaller XML Responses on the same release i.e. latest Final Release 2.0.4/WebAS 6.4 and was also working perfectly well on older Sneak Preview 2.0.0/WebAS 6.3 for both smaller and lengthier XML REsponses. Infact it was much faster. Also There has been no change in the application functionality and everything has been the same as it was on the older version. In short there has been no change at all.

kindly advise on any missing configuration/optimization tuning practice that might be required to improve the response time and eliminate these XML Deserialization Errors. When i tried executing/testing the same web service from the SAP's Web based UI for testing Web Services, i figured out that the Web Service took a lot of time in returning the XML response which was lengthy and it seems what the Deserialiser got was an incomplete chunk of XML Response.

kindly advise.

.V