altering the name of the public schema

[restarting the "Renaming schema's" thread from pgsql-general]

Using pgAdminII version 1.4.2 with PostgreSQL 7.3

I can alter the name of a schema using:
test=# update pg_catalog.pg_namespace
test-#     set nspname = 'newname'
test-#     where nspname = 'oldname';

This works without a problem until I try to rename the public schema.
For some reason this schema doesn't list among the schema's in a
database anymore. Changing the name back to public will make it list
again. But, even when it is not visible I can perform queries on it.
psql does not have any problems.

If I just add another entry into the pg_namespace table using an insert
query it will show straight away as a schema in pgAdminII. So I presume
the issue lies in the one thing I can't control in the pg_namespace
table; the OID.
Could it be that somewhere in pgAdminII there is a reference to the OID
2200 that is assigned to the public schema by default?

Jochem