Nope I haven't used it either. Though I'm giving my thoughts below.
As you already mentioned, communication with the camera is via a serial link. I think the protocol is just text, send text command ie "PG" then expect "ACK" or "NCK" as a reply. If it is then it would be, relatively, very easy.
To test this, I think connecting teraterm (or Br@ys Terminal), with the recommended settings for the camera, to the RS-232 port of the camera and sending the commands and waiting for the responses as indicated in the document. If it works, then its just a matter of putting wrapper code to send the commands and wait for the responses, and having a buffer where the image will be saved.