case insensitive match in unicode

[SunWuKung <Balazs.Klein@xxxxxxxxxx>]

I would need to do case insensitive match against a field that contains 
text in different languages - Greek, Hungarian, Arabic etc.
The db encoding is UTF8.

So far I found no way to achieve that. I tried converting both strings 
to the same case and using ~* , but neither worked.

Does anybody no a way to do this?

Thanks for the help.
Balázs