I connect to the internet with an USB DSL modem. I want to share this connection over AirPort. I have a wifi WPA2 network which is provided by an AirPort Express. In the system preferences > sharing I can select AirPort, but have to create an unsecure WEP network. How can I share the internet connection over my existing secure WPA2 network. I don't want to create an extra unsecure computer-to-computer network but share internet over the WPA2 network for all computers that connect. I hope you get what the problem is. I would be very thankful for any help or advice from you.