[Xymon] Demotool

I am interested in using this to create a testbed. From what I can tell, it only sends a message that contains the [date], [uptime], and [free] sections of the clientlog to the server, so how are the rest of the columns created, by the xymond daemon?

Is there any simple way to add ones own columns to this structure and have them show up on the server?

Thanks, David