[TheOnly-a.k.a.-Jon]

It does work for MOHaa on my computer.
So it can work on yours.

[Michael]

doesn't work on mine either. the special signs aren't replaced with ???'s, they're replaced by .........
it's wierd.

[TheOnly-a.k.a.-Jon]

All of the alt codes works well in chatscreen.
Part of them is represented by a ? in the score.

Examples that work fine for me in both chat and score:
(I think approximately half of the total list on the linked website)
€
™
©
®
±
¼
½
¾
alt-0192 until alt-255