C collation and Template 1

Hi,
I tried to create the following database:

CREATE DATABASE testing
WITH ENCODING='UTF8'
OWNER=postgres
TEMPLATE=template1
LC_COLLATE='C'
LC_CTYPE='C'
CONNECTION LIMIT=-1;

And received the following error in pgAdminIII:

"An error has occurred:
ERROR: new collation (C) is incompatible with the collation of the template database (English_United States.1252)
Hint: Use the same collation as the template database, or use template 0 as template."

To my understanding Template 1 allows the postgres user to perform housecleaning/administrative tasks such as Vacuum Analyze, Template 0 does not contain those privileges.

My ultimate goal would be to use the C collation and Template 1.
Why are the two incompatible?

Thank you,
Sincerely,
Kasia