Oops. You are right of course. I am referring to the Automattic Plugin that came with the German WordPress 2.2
In WordPress 2.2 (running on a Server with PHP 4.4.3) I managed to solve the problem in this way:
in wp-includes/class-pop3.php I commented out line 372 "continue;
I admit it was a bit of guesswork. I did not study the logic in depth, but I found out that in wp-mail.php $bodysignal never got set to true because the empty line that serves as the signal for the beginning of the body did not get written into the array $message.
If you are a coder you will understand what I mean.
If not, just try it and hopefully it will work for you too 🙂
Martin