Trouble with latin2 file names under utf8

[doppler]

I just upgrade my gallery from older version to 1.5.12. This is quite old gallery, and lots of files has non-english characters in the file names. I change whole database to utf8, also use utf8 charset in gallery. Everythink is set for utf8. But those pictueres with filenames like "gęśla.jpg" are not shown in gallery.

Somebody has an idea how to deal with it?

(If I include new picture like "gęśla.jpg" - everything is OK byt filename is changed automaticly to "gesla.jpg")

My gallery has more than 30.000 pictures. Changing this manually is impossible.
Old gallery was in latin2 (polish).

[Αndré]

I assume you have to undo:

I change whole database to utf8, also use utf8 charset in gallery.