Unique index problem ?!

[pawel jankowski]

Hi !

I have unique index on varchar field, charset is UTF8 and collation is utf8_unicode_ci.
When I try INSERT a two new records - some like that:

1) ..., 'slusarz', ...
2) ..., 'ślusarz', ...

then mySQL throw's an error: "#23000Duplicate entry 'ślusarz' for key 2" , why??
characters like 's' and 'ś', 'a' and 'ą' ... etc. are different from themselves and they have different codes in UTF8 charset.

Please help