Well, you can listen to the PUBLIC_MESSAGE and PRIVATE_MESSAGE events that are fired at the Zone-Level.
In those events, one of the parameters is the SFSEventParam.MESSAGE, which contains the message that was sent. You can use it for logging purposes.
For more information, please check the SFSEventType
//SFS tutorials: http://sfs-tutor.blogspot.com/
- I no longer update it. Some examples may be bugged