Postfix HOLD method

[Peter Russell]

Hello, could anyone offer me some tips on improving the HOLD method for 
postfix?

my header_checks file contains
]# vi /etc/postfix/header_checks
# For MailScanner
/^from userid 0/ OK
/^from userid 89/ OK
/^Received/ HOLD

Some one suggested this a while ago as a way to hold messages for 
checking that are inbound but not ones released from quarantine via 
mailwatch.

For some reason it doesnt work anymore and i have changed anything.

Whats the best way to achieve this?

Thanks in advance
Pete