exclude user mappings, foreign server from dump

Hello,

I have the question regarding pg_dump functionality.
I using PostgreSQL 8.4.8 database and defined the dblink between two
databases. dblink uses foreign data wrapper, user mappings and foreign
server.
When I perform database backup using pg_dump utility it also includes
foreign data wrapper, user mappings and foreign server definitions. However
since it isn't related to the schema itself I would prefer to exclude this
information.

Could you please suggest me if is there a way to not dump foreign data
wrapper and user mappings in pg_dump (exclude this information)?

Thank you.

--
Sergey