There is a Keyboard Compatibilty list here:
...but this is not official and isn't really complete (I use a Cherry Industrial one and it works fine).
The newest firmware is 3.2E. Try updating to that and seeing if it works.
Is this true ? The link above includes wireless keyboards.
Does anyone know if Nintendo intend to release a wireless keyboard for the Wii? I would like to see one with an incorperated pad/track ball as I find using the wand a bit difficult on the internet channel.