To make life easier I've made a script called freeswan-script at
http://jebc.dyndns.org. You will need to edit where ipsec is (/usr/sbin/ipsec). And when it asks if you want to install, say no unless you have setup rsa authentication from you to the gateways.
The problem above is due to config file problems and ipchains. The script will make great config files, and the ipchains is taken care of by editing the 39ipsec-net file, expanding, and then making sure that that rule above is loaded before the MASQ'ing rule.
Again, any questions or comments can be mailed to jebc@utk.edu
Thanks,
Jeb