White listing

Hi,

Debian (Alpha) 3.1, SA-Exim-Version: 4.2.

I am trying to find a effective way to whitelist senders. 

I have been using a web interface to SA's 
$f->add_address_to_whitelist($addr) to allow users to whitelist 
senders. However this method uses the auto whitelist (AWL) and I am 
told that this it not the best suited to whitelist senders. The best 
practise, I am told, it to either add the senders to a *cf file in 
/etc/spamassassin (involves a HUP) or better still in a exim 
whitelist.

What I am stuck on is how to enable local_sender_whitelist

The file exists:
-rwxr-xr-x www-data root  /etc/exim4/local_sender_whitelist

There are files in the acl dir that refer to 
CONFDIR/local_sender_whitelist but I am not certain they are being 
used. However in my tests users that have been added to the file are 
still being scanned and failing. It is becoming quite a problem as 
the number of false positives seems to be increasing.

Ideally I would like entries in the local_sender_whitelist to be 
stamped with the warn X-SA header that allows them to be skipped from 
normal scanning but I'll settle for any thing at this stage.

Any help would be appreciated.
TIA.