Newbie Question: Correlation when no matching elements exist
I have a request with an order number that gets sent to another BPM for a lookup. If the order number exists, the called BPM responds with returnCode=0 and the list of order contents (along with the order number).
However, if the order number does not exist, the called BPM returns just one element returnCode=1 and nothing else.
How can I create a correlation in this situation? One simple solution might be to change the response to include order number whether the order exists or not.
But, I am wondering if XI (3.0 SP13) has any other way of generating its own correlation-ids or keys (pardon my usage of terminology if it's incorrect) - instead of depending on defining the matching elements in the involved messages?