[exim] Mainlog recording incorrect sender

I am having trouble getting Exim 4.5 to log the correct sender. My
server name is 'proxy' and when I write a message from
'test@???' to 'test@???' the log records the correct
recipient, but shows it as being sent by 'mail@proxy'

What is causing this? I have had a look through the docs, and tried
adding log_selector = +received_sender to the config file.

I've also checked through the source, and it seems the variable
sender_address is the value which is being incorrectly reported, or at
least reported differently to what I am expecting.


This problem technically isn't a high priority, but it means that
bouncing will never work, and neither will eximstats.

I'd appreciate some advice on this one.

Regards
Richard