If you force your ESSID in /etc/conf.d/wireless and that ESSID needs a WEP key, which you also specify with key_ESSID, that WEP key is ignored. The problem lies in the iwconfig_associate() function in /lib/rcscripts/net.modules.d/iwconfig. In baselayout-1.12.0_pre10, lines 342-345 disable the key because $4 ($wep_required) is not given when the function is called from line 776. Removing lines 342-345 solves the problem. If a key is given for an ESSID, I think it should be assumed that that key is necessary. I then realised that I don't need to force my ESSID anyway. I used to have to but the very very latest madwifi driver seems to pick it up automatically now. (-:
Created attachment 72553 [details, diff] fixes issue
Ah yep that's a better idea!
Fixed in pre10-r1