No response headers are accessible from an amf request

I'm trying to capture the response headers (specifically Set-Cookie) from an amf request. In the Headers Tab within the UI, there are 6 headers returned, including Set-Cookie. However, the following calls within a Script Assertion (within the Test Step that makes the amf request) are returning no values.

* this returns 0 *
def responseHeaders = messageExchange.getResponseHeaders()
def test = responseHeaders.valueCount()

* this returns null *
def rawResponseData = messageExchange.getRawResponseData()
def test2 = rawResponseData.toString()

Response Headers visible after the amf request (within the Headers Tab)
Date Thu, 27 Oct 2011 15:14:53 GMT
Content-Length 3899
#status# HTTP/1.1 200 OK
Set-Cookie JSESSIONID=6A2D7A5B41F16DB2038104348455EE48; Path=/
Content-Type application/x-amf
Server Apache/2.2.14 (Ubuntu)


We are currently using the trial phase of the Pro version and are currently stuck at this point.

Thanks!
-Stephen