What's your $LANG variable?
In my case it's $LANG=en_US.utf8 ("utf8" makes the difference).
If your locale is not set to utf8, set it.
Then mount your NTFS partition with:
mount -t ntfs -o iocharset=utf8 /dev/hdxx /mnt/ntfs
File names should be displayed correctly.
NTFS uses utf8 charset.