WDS option are hidden in "Advanced wireless" on firmware 1.23WW (i don't know if it is on another version)
(http://thumbs.subefotos.com/8f3380e66850a64c08c4e4ca8965aaaco.jpg) (http://subefotos.com/ver/?8f3380e66850a64c08c4e4ca8965aaaco.jpg)
MAC address can be saved, "WDS Enable" not :(
There are a lot of hidden options in all the control panel ;)
Sorry for my english :D