I used something like this to move files from a customer upload location on our site DMZ to a secure location on our internal network. I a believe that this will allow you to do what you want. My memory may be a bit rusty... but I seem to recall having a perl program which parsed the log files and noted completed transfers, moved the files, and kept track of which files had been moved. We fired off the process every 10 minutes via cron, but a daemon would have worked just as well. The daemon ran inside the firewall and used scp to reach out to the DMZ ftp server and grab the log. It then processed the log and grabbed any new files, again via scp, keeping track locally of files which had been already recieved/moved.

Probably not exactly what you had in mind, but it worked for us at the time.