Hi
The Wlan On/Off is controlled by software.
As far as I know the FN buttons controls the Flash Card Utility which is part of the VAP value added package (in most cases). So my first idea would be running an VAP.
Additionally update the Wlan driver. Here is the Toshiba WLan portal containing all available wireless drivers:
http://aps2.toshiba-tro.de/wlan/