Here my update (german/english) for the ones who are using a router in the WLAN and have the newest firmware (6.3.0.2) on the WLAN card. You can download it from my homepage (using the link tutorial at the bottom of the page)
http://homepage.hispeed.ch/Waldkatze.../BtNindex.html.
More or less you can use the tutorial also for older firmware versions when you want to set up your WLAN card with a router in your network.