NetworkManager: how to restrict wifi on an interface

[Andrea]

I have a brand new F13, KDE.

I have a laptop with 2 wifi cards and I would like to use only one of them.
The integrated one is slow, I want to use the pcmacia

Network manager has an option to restrict a connection to an interface but as soon as I select it,
no more connection and I get the message "unavailable" or disconnected in the tray icon.

So far the only solution has been to blacklist the driver of the ipw2100.
I feel NM should be able to handle it.

Andrea