Can anyone provide guidance on using referrals on consumers with glued directories?

For example if I have a root of dc=bar, with a separate database glued as o=foo,dc=bar. Replication works fine in o=foo by configuring it on dc=bar.

Configuring an updateref on dc=bar also works for updates to dc=bar, but does not work for updates to o=foo.

I can't add an updateref to o=foo as there is no replication defined on that database.

How can I configure this to provide referrals from all glued directories?

Nick