sorting in UNICODE table

I'm use postgresql-7.0.2. It's compiled with unicode support
(./configure --enable-multibyte=UNICODE ...)
I have a table which contains both latin and non-latin letters. All they are in UTF-8 encoding. When
I try to sort the rows

( SELECT * FROM my_table ORDER BY sort_field )

I receive strange error: the rows that begin with ascii symbols are ordered while all other - are not!

I guess this is because UTF-8 strings are sorted in the order of the
physical representation. Can you show me sample data and its desired
order?

--
Tatsuo Ishii