Last December, I brought this problem up on p5p:
in reply to Win32 API directory searches that return wide / unicode filenames
No one had any good solution for it.
Ideally, perl/win32.* will be updated by someone (or by me) to support the Wide functionality. It's rather a huge shortcoming, when standard tools like File::Find and opendir() won't work at all. It's hard to write cross platform code that way when Win32 _Perl_ is fundamentally broken wrt Unicode filenames.