[otrs] Attachments not showing up in emails

Hi, I have had a couple of people complaining about not receiving attachments that I have sent from within OTRS. Checking the logs on the SMTP server I can see that the emails have a size that must include the attachment. But it is not there when I open the email in Exchange. This behaviour started in OTRS 3. Has anybody else experienced this and found a possible cause and solution to it? Lars