WEP Wifi Connection Problem
64-bit WEP key in ASCII mode is 5 characters, and since you've said your WEP key is 0e39c004e1, you have to enter it in HEX mode. I'm not sure if your phone can handle HEX input, so if I were you, I'd try to (temporarily) assign some other WEP password, which can be entered in ASCII mode (5 random characters, letters or numbers), and see if that works from your phone.



Since you've mentioned that both your phones, Xperia X10 and Xperia S have the same problem with this router, it might be a good idea to invest about $30 in small WiFi router, which can connect to your home network and serve internet to your phones and other wireless devices. I use TL-MR3020 and it works perfectly in many situations.