Offline Fulltext Catalog - how to remove from sys.database_files

Hi,

I have inherited a few SQL servers with a number of databases all exhibiting
the same problem.  They all had a missing Fulltext Catalog file which was
causing errors on backup.

I sorted most of them by dropping the the full text catalog using DROP
FULLTEXT CATALOG.

However 6 of the databases report no fulltext catalogs exists even though
sys.database_files has a entry for a fulltext catalog called
sysft_DatabaseName on drive S:.  Neither DROP FULLTEXT CATALOG or ALTER
DATABASE REMOVE FILE work.

5 of these I managed to fix by creating and then deleting a new fulltext
catalog with the same name as that listed in the sys.database_files table.

However - the last database has been moved to a SQL 2008 server and my
solution of creating and deleting a new fulltext catalog doesn't work and
unfortunately you can downgrade the database to SQL 2005.

How can I removed the ftcatalog entry from the sys,database_files table?

Thanks,
Daniel