Extending AirPort - two networks visible to PCs?

[Turboladdade]

I just bought an AirPort Express N to extend the network broadcasted by my existing AirPort Extreme N.

I enabled "Allow this network to be extended" on the Extreme, and put the Express into "Extend a wireless network" mode and configured it as necessary. I must have done it right because now all my Macs see the original network (named PrivateWiFi-N) as before, but now receive the signal more powerfully, and the Express shows a green status light. So far so good...

However, on my brand new Windows 7 laptop (the only Windows machine I have), it only sees a network with SSID of PrivateWiFi-N 2, not the original (without the "2"). Attempting to connect to this 2 network results in failure. But by manually setting up a wireless network connection, and typing in the correct SSID, my Windows 7 laptop successfully connects to it.

So my question is, why is this happening? Is this normal? Or is there something I can do to correct this? I don't want to have to tell guests to manually setup a network connection on their PCs just to connect. And, despite the fact that it works, just knowing that it's like this bugs me.

Any help appreciated. Picture attached below.

[leonAzul]

Sorry I didn't see this sooner; I hope it didn't cause any trouble for you over the holiday weekend.

I note that you have given the base station the name "PrivateWiFi-N". Does this mean you have it configured as an 802.11n Wireless Access Point? According to Apple, you need to restrict it and the other WAPs to 802.11g in order to allow it to function as a Wireless Distribution System (WDS).
http://support.apple.com/kb/HT4262

WDS is designed for 802.11g, and shouldn’t be used for 802.11n devices. Wi-Fi base stations may include AirPort Extreme (802.11g) and AirPort Express (802.11g).

Your Macs are probably set up to connect to the first WAP on the list of previous connections (the default behavior) whereas the default for Windows (unless you change it) is to connect to the strongest. There really should have been some sort of error message from the Airport Utility to let you know the clone operation didn't take place correctly instead of failing silently, albeit gracefully.

[Turboladdade]

Well I followed Apple's instructions exactly and it did work as far as the Macs are concerned - there is only one network visible to Macs. Only PCs see "PrivateWiFi-N 2".

And for the Macs this one network now has more bars where before it only had one or two.

I used the "extend network" not the WDS stuff.

[leonAzul]

Sorry, I misunderstood.

That's. Weird.

You've probably already tried resetting both stations, clicking "Allow Extended" for the primary and "Extend a wireless network" for the secondary, so the only other thing I can think of is to try again using the Windows version of Airport Utility.

ETA

I did think of something else. Check to see if there isn't some sort of MAC address filtering going in in the Windows connection manager that is causing them to see the WAPs as different machines with colliding names instead of an extended network. If you can't resolve it that way, you may need to log in on the second WAP as a sudo-er and "adjust" the MAC address.