Latvian language & upper & lower

I have postgresql 7.3.2 on Mandrake 9.1.

pg_controldata returns:
LC_COLLATE:                           lv_LV.UTF-8
LC_CTYPE:                             lv_LV.UTF-8

but when making upper or lower on any text latvian symbols stays on the 
same case. And I can't get lower and upper to work correctly :( Is there 
any such way to get them work correctly? :)

Thanx anyway :)
Lafriks