Ok, here's a test senario ... one has to figure out IF it's moodle process or Postfix that's stripping out stuff.
On the Ubuntu server create a shell account called 'hpotter'. Then, in Moodle, manually create an 'hpotter' account and for that users EMail address, point it to the moodle server itself - from what I've read from headers that should be:
hpotter@tes-moodleserver.my.dom.ain
Postfix on that server shouldn't relay but deliver that message locally to hpotter account.
Create a minimal "test" category and course. The 'test' course has only one student enrolled ... that of hpotter.
Subscribe hpotter to the announcements forum in the 'test' course.
You, as an admin level user, should be able to post to that forum.
Run the cron job from command line ... look for indication that forum postings are being sent to hpotter. If you send immediately, check server logs ... the mail server logs.
su to hpotter's account and check the mail.
If the message is delivered in tact ... ie, the posting shows as it should, then Moodle code *IS* attempting to deliver the content of the message as it should ... ie, nothing wrong with Moodle code and the sending of the message.
The only other thing I see that *could* cause Windows systems issues is that of the 'admin' user addy being used.
admin@my.dom.ain - what of changing to moodleadmin@my.dom.ain (that account must exist in the Windows mail systems for it to be used).
'spirit of thinkering', Ken
