warm standby question

Hello -
I am working on setting up warm standby for one of my servers and I am a
little confused about the documentation. I am using pg_standby on
postgres 8.4.1 running on linux.
My recovery.conf is very basic:
restore_command = 'pg_standby /shared_pitr %f %p %r'
On the secondary, I can see two processes:
postgres: startup process waiting for 000000010000000000000037
/services/8.4/bin/pg_standby /shared_pitr 000000010000000000000037
pg_xlog/RECOVERYXLOG 000000010000000000000020
which does in fact refer to what would be the next WAL file.
Based on the documentation, it looks like the wal files that have
already been replayed should be automatically removed from the archive
directory by using the %r macro. This does not appear to be happening.
Do I have to write a script to remove archived wal files prior to
000000010000000000000037, or do I have the system set up incorrectly?
Thanking you in advance for any help!
Mija

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