I just bought 500g, it has the latest firmware.
I configured desktop PC via 500g and Chello modem, no problems.
I configured notebook with Dell (Broadcom) TrueMobile 1300 mini-PCI card (WinXP) to use WEP 128-bit. No problems. DHCP server in 500g accepts the notebook and gives it IP, connection is good, fine.
But as soon as I change the encryption to WPA-PSK (AES or TKIP, does not matter, I tried both), it does not work.
Here what happens: notebook recognizes the SSID, connects(!), but no traffic occurs. There are a lot of sent packets from notebook, but 0 recieved. Hence notebook does not get an IP address from the DHCP server.
I suspect the advertised WPA encryption is not really operational?