problems with changing the case of turkish characters

Just want to clarify if there is something I've overlooked or if this is a known issue in PG 8.4 and 8.3

 

 

CREATE DATABASE test
  WITH OWNER = postgres
       ENCODING = 'UTF8'
       LC_COLLATE = 'English, United States, UTF-8'
       LC_CTYPE = 'English, United States, UTF-8'

 

 

select ('İsteği') from tversion
"İsteği" was expecting "isteği"

 

select upper('iışğüçö') from tversion

"IıŞĞÜÇÖ"

 

select lower ('İIŞĞÜÇÖ') from tversion

"İişğüçö"