Quassel IRC

I'm not good at english, so maybe i had a lots of grammar mistakes on my statements.
When I using quassel, I'm encountered that i can't make my nickname with korean.
But, that's okay. I still using my nickname without korean.
Chatting is fine, anything language is working with quassel very well.
When I querying irc channel users, some users can't qurying with me.
At first, i don't know what happened.
When i view that user's info, i saw most of his nickname is broken with few question marks.
Than i realized that the broken characters is not alphabet, number or special characters.
I think quassel have some trouble with asian characters.