Join a WPA2 Enterprise network with an airport express

Im having this exact problem. Anyone have any hints?

My TimeCapsule is creating a 5ghz N-network which is configured to use WPA2 Enteprise and RADIUS on my OS X Server. Everything works fine on my two wireless clients (iMac and MacBook), and everything was working fine on my AirPort Express when I was just having it join a regular WPA2-Personal secured network.

Now the APE dont even find the 5ghz N-network. When I switch to "Join wireless network" the options regarding access and radio modes disapear. I type in my ssid and choose WPA2 Enteprise. Then hit update.

The AP utility prompts me with to errors requiering radius IP, and shared secret. But nothing happens when the device comes back up. It just doesnt join the network...

If the Apple website is accurate, you cannot join any network using WPA2.

"When joining an existing wireless network, AirPort Express supports only WPA-Personal. WPA2 requires a Mac computer with an AirPort Extreme Card and Mac OS X v10.3 or later."

http://www.apple.com/airportexpress/specs.html, Footnote 3

I'm not sure what that means though. I was able to have the Airport Extreme join my WPA2 network served by a ATT 2WIRE DSL router.

However, since changing to WPA I can't get the AE to join the network...

I'm not sure what that means though. I was able to have the Airport Extreme join my WPA2 network served by a ATT 2WIRE DSL router.

I would guess that the 2Wire router is allowing both TKIP and CCMP (AES) clients to connect and not restricting to only CCMP (AES) ones. In that case, the AX can join this wireless network using the TKIP cryptographic protocol. WPA only allows for TKIP; whereas, WPA2 allows for both protocol types. Actually some manufacturers confuse this a bit by providing a WPA setting on their routers that allows for both types as well.