How can I modify the configuration for a postgres-8 resource managed by a RHEL High Availability cluster with rgmanager?

Issue

• Is there a way to modify the configuration of a cluster-managed postgres instance and apply it without restarting the service?
• Need to change configuration file: postgresql.conf for database in Red Hat HA cluster, but Red Hat HA is using a copy of the original file in different location at /etc/cluster/postgres-8/, which prevents me from updating the configuration and being able to reload it with pg_ctl reload.