At last, I've configured OpenZaurus on my Zaurus SL-C1000 (akita), with a CF wifi card (DLink DCF-660W) in order to be able to connect to my WPA wifi network, provided by the Freebox.
It required configuring wpa_supplicant and changing from the default orinoco driver to the hostap one. Details on such setup here.
Tada ! it works beautifully :)
Now, It becomes a little bit more useable.