
To indicate to LJ that your client supports UTF-8, you need to set the "ver" key on your requests. People who don't send the key are assumed to be at protocol version 0; version 1 is identical to zero with the addition of UTF-8 support.
Here's my login input from LogJam:
mode=login&hpassword=snip&getmenus=1&getmoods=134&getpickws=1&cli
(Hopefully