I posted this a reply to another thread, but actually it is best linked here. I still have been unable to get this to work, but maybe this info would spark some imagination: The rest of this info is submitted under my own investigation and in no way should be deemed as a Cisco recommended practice - still it good to tinker 
The rules are actually based on the IPTABLES command built into Linux which can be accessed from a root login. However, I have tried to run an 'iptables-save' on one box and and 'iptables-restore' on a Test VCS, and although I see the changes using 'iptables -L', they do not appear in the web interface and that are wiped on reboot.
It looks as though the iptables command is manipulated through a Python script called 'iptablesd.py' located in '/sbin' directory and a log is written to '/mnt/harddisk/log'. You can even see where the User Firewall rules are wrtien out to, which is '/tandberg/persistent/user_firewall_ipv4.conf'. This file seems to be read in on boot to build the IPTables rule list, but manipulating it directly didn't appear to do much good either as it seems to be over writen during the shutdown sequence.
I'm not sure if x8.1 makes up for this deficiency as we havn't got around to testing it yet, but I will keep digging to see if ther is a way to manipulate this.
Chris
