Nick is right because the ReplytoNode is a specialized version of MQoutput node, which in turn is exactly same as specifying ReplyToQueue option for Destination Mode on MQOutput ...
I know that the MQSeries-IMS bridge accepts a multisegment IMS transaction data along with a MQIIH structure
"MQIIH LLZZ trancode data[LLZZ data][LLZZ data]".