The ReplyToQueue is sent on the message header, so you must get the message with the header (-HDR) and parse it from there on your input card.
Here's the doc about the adapter's command: http://pic.dhe.ibm.com/infocenter/wtxdoc/v8r4m1/index.jsp
You should have a type tree on the Examples to read the message with a header.
Regards, Bruno.