I would say the easiest way to configure this would be to have FW1 forwarding any required traffic to the DMZ (orange interface). Any traffic that is meant for the internal network (via firewall 2) should be sent to the red ip of firewall 2. Firewall 2 then needs to be configured to forward required traffic from the red network to the green network.
Not sure if you are using Endian FW for both, but if you are I would recommend using the one firewall to keep updates nice and easy