Hey extasee x,
Thanks for letting us know what you've tried and I see that you've set up a static ip address for your console. Maccabi walked your through how to set up your ports here xbox one nat type help. When you set up your connection did you set up both your Xbox One and Xbox 360 to separate static ip addresses? When you set up port forwarding, which ip address did you use? Port Forwarding will help to direct the inbound and outbound traffic to the port numbers your designate, but if you have port forwarding set up on one ip address, it may interfere with another from accessing those ports. You can try setting either your Xbox One or your Xbox 360 to DMZ so that your may have the ports forwarded to one and opened for the other.
Thanks,
^AJ