This version of RESTLog that I am running also supports the CommentAPI. The easiest way to explain it is that you can post a comment via posting an RSS item fragment. Here is how you would do it with cURL:
curl --header "Content-type: text/xml" --data "<item><title>Joe</title><description>Posted via cURL.</description></item>" http://bitworking.org/news/comments/52
Note that the above is typed in as a single command line, just broken up here to fit on the screen better.