obj_description problems?

How do I use a schema-qualified name in obj_description?  Or is this a 
nsty little bug?

Chris

test2=# create schema myschema;
CREATE SCHEMA
test2=# create table myschema.pg_class (a int4);
CREATE TABLE
test2=# select oid from pg_catalog.pg_class where 
oid='myschema.pg_class'::regclass;   oid
--------- 1475161
(1 row)

test2=# select obj_description('1475161', 'pg_class'); obj_description
-----------------

(1 row)

test2=# select obj_description('1475161', 'pg_catalog.pg_class'); obj_description
-----------------

(1 row)

test2=# set search_path to myschema, pg_catalog;
SET
test2=# select obj_description('1475161', 'pg_class');
ERROR:  Attribute "relname" not found
test2=# select obj_description('1475161', 'pg_catalog.pg_class');
ERROR:  Attribute "relname" not found