WAL replication wrong collate

Hello,

i try to replicate my database. what i have done?

- create a cluster on slave (UTF8, en_US.utf8 collate/c_type)
- stop cluster and cleanup datadir
- do basebackup from master
- start db-cluster

Master has utf8, en_us.uft8 collate/c_type
Now my db on slave has UTF8, c.utf8 collate/c_type.
Whats wrong here?

master and slave had set the same locales.
I dont unterstand that i can create a database in en_us.utf8 and then
when i did the basebackup it's change to c locale.
I cant find any option for pg_basebackup to set locale/collate.
I use this howto https://wiki.postgresql.org/wiki/Streaming_Replication
and had install an other cluster in the past with successful.

How can help please?

Best regards,
basti