Andy Oliver is now back on JBMail, the mailserver project that he started. The first preview that I got in hands wasn't that useful, as it made some wrong assumptions about DNS servers.
In contrary to the last release, this preview is a binary one, including the whole ant 1.6.1 distribution (30 MB unzipped) :-( That at least explains why the package is now so fat.
But after this, the install runs fine if no TLS is used.
Running the mail service is still a little problem for me, as the name resolution doesn't quite work, but here on my Windows box, I am not able to tell if this is a problem with JBMail or Windows itself.