Some years ago when I first bought a Cardphone 2 I digged around the message board asking some questions.
As far as I recal not once did I get any answer from somebody with actual knowledge, such as...

The manual clearly state that D211 does not support voice operation

They are not to hard to find, go to the homepage for the product and hit download ;)

http://www.nokia.com/phones/productsupport/d211/downloads.html

How frustrating ;(
It just doesnt work wihout WEP configured, and WEP isnt really an option in our nets.
Digged around in the source, it seems like the wep controlling code is berried in the binary...

I got the same problem, thought somebody had fixed it ;)
I'll guess I have to dig through the source myself, if I find it I'l post