enum types and binary queries

I noticed that enums are not available to be queried as binary through
the protocol.  Is this a known issue?  Too late to fix for 8.3?  This
is kind of a pain, because it forces any query that returns an enum to
return the entire result as text.  afaik, enums are the only POD type
to behave this way.

postgres=# create type foo as enum('foo');
CREATE TYPE

postgres=# copy (select 'foo'::foo) to '/home/postgres/foo.txt' binary;
ERROR:  no binary output function available for type foo

merlin