Mail misses header (blank subject and sender label not defined)

As described here (http://www.jroller.com/melix/entry/apache_cxf_maven_javamail_awful), e-mails produced using geronimo mail are not valid (subject is missing, sender not properly set) due to the content of the DATA section. While Sun's implementation produces this :

DATA
From: "I am the sender"
To: recipient-AT-somewhere-DOT-com
Message-ID: <1484678.01202984955533.JavaMail.me-AT-server-DOT-com>
Subject: an empty subjet for starting

the content of my mail

Geronimo only sends this to the SMTP server :

DATA
the content of my mail

Looks like the mail misses the header.