Unable to create one floating IP, not a range

From operators mailing list: http://lists.openstack.org/pipermail/openstack-operators/2012-March/000560.html
It's impossible to add just one floating IP to the pool of available addresses. In case if network has limited address space, not splited on segments, it's handy feature to just add IP addresses one by one that are available on the network.

I can't do this now:
stack@baseubuntuserver:~/devstack$ nova-manage floating list
2012-03-05 00:55:36 DEBUG nova.utils [req-2972cb1e-cd12-48f0-a73a-5449110f8eda None None] backend <module 'nova.db.sqlalchemy.api' from '/opt/stack/nova/nova/db/sqlalchemy/api.pyc'> from (pid=5303) __get_backend /opt/stack/nova/nova/utils.py:607
No floating IP addresses have been defined.
stack@baseubuntuserver:~/devstack$ nova-manage floating create 192.168.253.5/32
stack@baseubuntuserver:~/devstack$ nova-manage floating list
2012-03-05 00:56:01 DEBUG nova.utils [req-78b72a1d-7b29-4e8f-877b-25460d1c02e5 None None] backend <module 'nova.db.sqlalchemy.api' from '/opt/stack/nova/nova/db/sqlalchemy/api.pyc'> from (pid=5315) __get_backend /opt/stack/nova/nova/utils.py:607
No floating IP addresses have been defined.
stack@baseubuntuserver:~/devstack$ nova-manage floating create 192.168.253.5
stack@baseubuntuserver:~/devstack$ nova-manage floating list
2012-03-05 00:59:10 DEBUG nova.utils [req-a3eeb99b-e7f1-4e51-91e0-8b68528e1e7f None None] backend <module 'nova.db.sqlalchemy.api' from '/opt/stack/nova/nova/db/sqlalchemy/api.pyc'> from (pid=5497) __get_backend /opt/stack/nova/nova/utils.py:607
No floating IP addresses have been defined.