Can someone please post an example paramsXML which has a non-empty <c:externalData> block that when send to Calais produces a valid RDF response?

no matter how i attempt to take advantage of the <c:externalData>
data block the resulting RDF triggers errors when i attempt to use tools like Jena to parse it because of the empty <c:CalaisSessionId/> tag added to it by Calais.

Types of errors i've been getting...

• Multiple children of a property element
• String data  "..." not allowed
• Cannot have both string data "..." and XML data <c:CalaisSessionId> inside a property element.

I freely admit i'm fairly a novice when it comes to RDF, there's a LOT i don't understand, and i'm sure many of the things i've tried aren't legal RDF, but several things i've tried parse fine IF i first manually remove the <c:CalaisSessionId/> block.

Can anyone show me a good example of using <c:externalData> ?