Jabber IM SDK (CAXL) does not have a live chat monitoring feature, and neither does Cisco IM&P.
However, if both participants are using a Jabber IM SDK (CAXL) web app that you write, you could write the web app to copy automatically all messages to a third client when they are sent. The third client (the person monitoring) would get all messages in the conversation. The people chatting wouldn't know that their messages are being forwarded to the third client unless you told them.
You could even write it so that the messages to the third client include identifications such as "Msg from email@example.com to firstname.lastname@example.org: How are you today?" That way you can see who is talking to whom.