It's easy to get OpenVPN client to work.
On Community release there isn't a Endian Client, you must use the standard OpenVPN client, which indeed it's very good.
Go to OpenVPN and download the client for your OS:
http://openvpn.net/index.php/open-source/downloads.htmlFor Windows the direct link is
http://openvpn.net/release/openvpn-2.1.1-install.exe(Latest release as of 15-feb-2010)
Install the client, and you just need two files to get your client configured:
1- A Certificate from your Endian's OpenVPN Server: You can get it from VPN->"Open VPN Server"->"Server Configuration"->"Download CA Certificate" green link.
You must have the OpenVPN Server enabled in order to see the download link
2-A config file. It's a text file with extension .ovpn. On that config file put this text
client
dev tap
proto udp
remote Your EFW RED IP address
resolv-retry infinite
nobind
persist-key
persist-tun
ca Your CA Certificate
auth-user-pass
comp-lzo
Save it with any name with extension .ovpn
Copy the two files (Your CA Certificate and your config file) to "C:\Program Files\OpenVPN\config".
And that's all. Using the OpenVPN GUI you'll have a new icon on the taskbar. Double clicking it will ask for user/pass, and with that you'll connect to your GREEN subnet.
Don't forget to adjust the VPN firewall, otherwise it won't connect to anything.