pg_dump not including custom CAST?

All,

I did this in my database:

   CREATE CAST (VARCHAR AS BYTEA) WITHOUT FUNCTION;

But when I use pg_dump to dump the database and use pg_restore to bring
it back on a freshly created database, the CAST is the only part of the
restore which is missing.

I'm using PostgreSQL 8.2.4 for both the dump and restore database.  Why
doesn't the CAST dump and restore?

-- Dante