Forum Facebook Account Integration and Weird Char..
 

I have set up my facebook developer account and integrate it with my forum..I also
enabled Auto-Register feature...When a user whose FB username contains ğüşı?ç any of this char, try to login to my forum by using facebook connect, facebook user is getting really strange username on forum like this G?¶khan Y?±ld?±z..(Gokhan Yıldız)

How can we solve this issue?
Regards..