I don't have IL-2 installed right now, but if I remember correctly, you have to go to il2setup.exe, click the Multiplayer tab, and change the IP from Default to another IP. If that doesn't work, try the next one on the list (if there is a next one). I had the exact same connection timed out problem and went nuts trying to figure it out until I messed around with the IP address on the settings panel.
EDIT: I haven't tried changing the RB3D settings as it seems to be working for me, but if you get IL-2 to work, try finding a way to configure RB3D to use that IP.