Q : iwl3945 doesn't want to register with WEP on a Conceptronic C54APM while
    the older ipw3945 worked fine with the same hardware.

    With version 1.2.25 of iwl3945 and kernel 2.6.24.2 connecting with a
    Dell Latitude 630 to a Conceptronic C54APM using WEP failed, however
    without WEP this combination worked fine.

    With the older IPW3945 driver the same combination worked fine, also
    with WEP. Initially I of course suspected the new iwl3945 driver, but
    after a lot of searching I decided to flash the access point with new
    firmware (I had 1.15 , now I use 1.25).

A : To my surprise after flashing the accesspoint everything worked
    flawlessly, also with WEP !

    So, there must be something fishy in the combination of the new driver
    and old firmware in this very popular accesspoint.