I was finaly able to get netcfg working with most of the wifi networks you can ran into, mixed WPA/WPA2 networks are still an issue though.
But I can't disconnect. "netcfg -d [network]" will fail and reconnecting fails too because netcfg think it is still connected to that network.
This is esspecially an issue, if the AP is gone for a while. Reconnecting is impossible after the AP is back.