Thanks for the fast reply!
The Extreme is an 802.11n model (although 1st generation). The Expresses are just b/g (early models, preceding Extreme). Had already tried the support guidelines for mixed models. During setup of the Express, all goes well until reboot. But green light never comes on (stays blinking orange), and I get an error message that Express could not find the network, and I should try again.
FYI, went through your guidelines on a different post...
Main Base Station Setup
o Click the AirPort status menu in the menu bar and choose the wireless network created by the base station you want to set up as the main base station.
o Open AirPort Utility (located in the Utilities folder in the Applications folder on a Macintosh computer, or in Start > All Programs > AirPort on a computer using Windows).
o Select the main base station, and choose Manual Setup from the Base
Station menu, or double-click the base station to open the configuration in a separate window.
o Enter the base station password if necessary. If the base station is using the default password of public, you will not be prompted for a password.
o Click Wireless in the toolbar, and then choose “Participate in a WDS network” from the Wireless Mode pop-up menu.
o Click WDS and then choose “WDS main” from the WDS Mode pop-up menu.
o Select the “Allow wireless clients” checkbox if you want client computer to connect to this base station.
o Click the Add "+" button and enter the MAC address of the base stations you want to connect to this base station.
o Click Update to send the new settings to the base stations in the WDS.
Remote Base Station Setup
o Click the AirPort status menu in the menu bar and choose the wireless network created by the base station you want to set up as a remote base station.
o Open AirPort Utility (in the Utilities folder in the Applications folder on a Macintosh computer, or in Start > All Programs > AirPort on a computer using Windows).
o Select the remote base station, and choose Manual Setup from the Base Station menu.
o Enter the base station password, if necessary. If the base station is using the default password of public, you will not be prompted for a password.
o Enter the same network password as the main base station, if necessary.
o Click AirPort in the toolbar and click Wireless. Choose “Participate in a WDS network” from the Wireless Mode pop-up menu, and choose the same channel as the main base station from the Channel pop-up menu.
o Click WDS and choose “WDS remote” from the pop-up menu.
o Enter the MAC address of the main base station in the WDS Main field. The MAC address is also referred to as the AirPort ID and is printed on the label on the bottom of the base station.
o Click Update to transfer the settings to the base station.
Followed all the steps - Express reboots, but keeps blinking orange and get message that new settings accepted, but cannot connect to network.Seems some kind of compatibility issue, but not sure where. Rechecked MAC addresses, and they're correct. Everything set up to run 802.11 n (b/g compatible). Channel and network name the same. I'm at a loss...
If you haven't already, temporarily connect both AirPort Express base stations to the AirPort Extreme by Ethernet; run through the WDS setup, and verify that all have a green status light after they restart.
Once verified, you can then disconnect the Express base stations, and then, move them to the desired locations.
I suppose that nothing is more frustrating than the guy who posts saying that "it works for me".
But, I've done this a few times following the step by step provided by Tesserax and also Apple and had no issues.....other than the WDS settings are really S-L-O-W in terms of performance.
So, it's probably a minor detail somewhere like an "O" (letter O) instead of a "0" (number 0), or an "l" (letter l) instead of a "1" (number 1) in the settings. It's easy to make a mistake and impossible to recover without starting all over again.
That fact alone might be good reason to avoid the WDS settings if possible.
Is the AirPort Express that you cannot get to work set to use the same Channel as the device that it is picking up a signal from?
The WDS settings do not display the Channel. You have to go back into the regular setup to make sure that both devices are setup to use the same channel. Then return to the WDS settings to match up the AirPort ID numbers.
In the past when I have had problems with WDS, it helps to have a second set of eyes.
My wife found a mistake instantly when I asked her to take a look.......and I would have sworn that I had the right settings since I had already checked 3-4 times.