Locale problem with LC_MESSAGES

Hi all,
I just installed cygwin/cygipc/postgresql 7.3 (i386 binary) on my W2K
box. Then I did a
initdb -W -D /cygdrive/d/apps/cygwin/usr/local/pgsql/data --locale=de_CH
--encoding=UNICODE

this seemed to work OK. Now when I try to start the postmaster, I get
the error message
invalid value for option 'LC_MESSAGES':'de_CH'

Can I supply a different LC_MESSAGES when there is none available for my
local language, but still keep the sort orderings of my locale?

I also tried locale de_DE with no change.

How can I make this to work? Does anybody have PostgreSQL 7.3 running
with german locale?
Regards
--Marcel