I've had an old Airport Extreme (802.11g) dome base station running a WDS network which I extended with an Airport Express (802.11g) as the range was very poor.

My Airport Express died so I went to buy a new one (now being 802.11n).

Boy!! I've spent close on 1 day trying to get it to work. Been on the phone to the reseller, then the Apple support line 4 times. I've checked discussion forums etc.

Seems that the 802.11n Express does not like to extend a WDS network. Finally, after being told to set the Extreme up as "participate" in a network and the "create a network" and the Express as "extending a newtork" (all of which did not work - death by a blinking orange light), I finally tried the one thing that the Apple techs had not told me to do - set the Express as "join a network" - and it worked!!.

The annoying thing was that each Apple person told me different things - none of which worked.

I'm still not sure that I did the right thing, but it now works!!