Watermark checking doesn't work

[Arjan Schrijver]

Hi people,

This watermarking feature sounds very good given all the spam 
backscatter I'm receiving the past weeks. So I set the following options 
in MailScanner.conf:

Use Watermarking = yes
Add Watermark = yes
Check Watermarks With No Sender = yes
Treat Invalid Watermarks With No Sender as Spam = spam
Check Watermarks To Skip Spam Checks = no
Watermark Secret = (this is secret)
Watermark Lifetime = 432000
Watermark Header = X-%org-name%-MailScanner-Watermark:


Now, the watermark is being added to each mail fine. I get the header in 
every outgoing mail. When I send a mail to a nonexisting address, it 
gets interesting. The DSN is being returned as it should, including my 
original X-%org-name%-MailScanner-Watermark header. However, MailScanner 
doesn't think it is a legitimate watermark, or it can't find the sender 
address. I get this logline for the DSN:

Apr  9 10:53:37 arenta MailScanner[32447]: Message 82BDF1E018B.CC35D 
from ######### has no (or invalid) watermark or sender address

Is there more configuration I need to do, or is this feature simply 
still in development and it doesn't work?

Kind regards,
Arjan