I have this in /etc/keystone/keystone.conf:

[DEFAULT]
admin_token = XXX
log_config_append=/etc/keystone/logging.conf

public_bind_host = 192.168.0.XXX
admin_bind_host = 192.168.0.XXX

rabbit_use_ssl = false
rabbit_userid = XXX
rabbit_password = XXX
rabbit_virtual_host = /
rabbit_host=127.0.0.1

[sql]
connection = mysql://keystone:XXX@192.168.0.1/keystone

[identity]
driver = keystone.identity.backends.sql.Identity

[catalog]
driver = keystone.catalog.backends.sql.Catalog

[token]
driver = keystone.token.persistence.backends.sql.Token
expiration = 14400

[policy]
# driver = keystone.policy.backends.sql.Policy

[ec2]
driver = keystone.contrib.ec2.backends.sql.Ec2

[ssl]
#enable = True
#certfile = /etc/keystone/ssl/certs/keystone.pem
#keyfile = /etc/keystone/ssl/private/keystonekey.pem
#ca_certs = /etc/keystone/ssl/certs/ca.pem
#cert_required = True

[signing]
certfile = /mnt/state/etc/keystone/ssl/certs/signing_cert.pem
keyfile = /mnt/state/etc/keystone/ssl/private/signing_key.pem
ca_certs = /mnt/state/etc/keystone/ssl/certs/ca.pem
ca_key = /mnt/state/etc/keystone/ssl/private/cakey.pem
#key_size = 1024
#valid_days = 3650
#ca_password = None

[token]
provider = keystone.token.providers.uuid.Provider

I would like to add this extension:

[trust]
driver = keystone.trust.backends.sql.Trust
enabled = True

1. How can I do that ?
2. Can I just type this in the file and everything will be working properly ?

I really don't know anything about keystone but I'm reading some stuff in order to achive my goal, any help or direction would be very appreciated.