it should be the same as the normal router right?

Just go http://192.168.1.1 and type username and password of your router (Airport Extreme). From there, try look for PPPoE section then key in your streamyx account username and pass. It should work that way

do you try to reset the airport? or update the airport utility yo latest version?

um... if using the AirPort Utility doesn't work... then try using a newer Mac, or installing the latest AirPort Utility, provided on the CD inside the AirPort Extreme box.

if that doesn't work, feel free to come see me at Mac City 1 Utama...

1) Your modem as provided by Tmnut must be set as "bridge" (I use this method)
2) make sure you connect your streamyx modem and airport extreme accordingly.
3) You cannot access the setting from your safari like normal router, please use the Airport Utility instead.
4) Click your "Airport Utility", and click "Continue" and fill up the blank accordingly.
5) Click "I use a DSL or cable modem using PPP over Enternet (PPPoE)
6) Insert your Account Name : abc@streamyx, Password and verify password accordingly,
7) Click the "update" button, voila you are connected to the internet.