Hi,
I have spend many hours but now its works for me.
2x WL500g with FW 1.9.2.7-7b connected with WDS and WPA-PSK TKIP.
What i have found out:
You can configure all settings with the webinterface but don't add the MACs under
Remote Bridge List and Access Control List.
I have add the MACs in the /usr/local/sbin/post-boot script:
-----------------------------------------------
#!/bin/sh
sleep 2
# WDS MAC from other site
wl wds 00:0C:XX:XX:XX:XX
sleep 2
# Client MACs
wl mac 00:13:XX:XX:XX:XX
-----------------------------------------------

I think when the MACs are in nvram the Router turns the wds on but it's not the right time to turn it on.That's why i have put the sleep to the script.