No device (wireless router) at mac address.

[Quicksort]

Platform: F17 x64
Dell Studio XPS
Dell Wireless 1505 draft 802.11n WLAN mini-card
Router: Livebox (Sagem)


Hello,

No problem to set my wireless LAN up under Windows7 x64.
I only have to input the SSID, the security mode and the WEP key.

Unfortunately Fedora' s network configuration tool system-config-network
does not find any device at the 
router' s mac address I have input (when I click "probe"), although this
router is connected to the ethernet port and
handles the internet connection which works fine. 

What' s wrong ?

Your insights would be most appreciated. Thanks.