We must not be talking about the same feature. Or something.
It supposedly can do either of: be a WiFi hotspot for WiFi clients if it has a path to the Internet and be a WiFi client to a nearby WiFi. Just with 3.5.1 you can't enter a key with any non-numeric characters when setting up the WiFi client connection.
If you want to see for yourself, I think the path is something like Menu | Settings | Wireless and Internet | Wi-Fi settings | Search for Wireless Networks. From there you can select an SSID to connect to. From there, if the network is not Open System, a key is required and you will be prompted to enter it. With 3.5.1, if that key has any non-numeric characters, it's the end of the game because MFT 3.5.1 is broken. (This did work in all prior versions we've had in our MFT-equipped FoFo since its 12/11 build.)
If you don't want to see for yourself, I'm OK with that too.