Actually I don't understand why that should be happening. The nickname is stored in a global string variable and when the user signs out, that variable is read and set to your nickname. In normal cases, this should support Unicode and I can't see why it doesn't do that.
If anyone else has anything to add, please do, because even script developers can still learn things.
Side note: a new version is being worked on, which will make use of the registry to save your original status information. If you can't work out this problem, I suggest you to wait a little longer and then try it with the upcoming version, maybe it'll work then.