Java EE (Java Enterprise Edition) General Discussion

So I want to send "text/plain; format=flowed" as described in RFC2646: http://www.ietf.org/rfc/rfc2646.txt

I'm currently using:

String message;
MimeMessage message;
// ... snip ...
message.setContent(body, "text/plain; format=flowed");

but this has the problem of the Content-Type being:

Content-Type: text/plain; format=flowed; charset=us-ascii

(note the second ; after format=flowed) which isn't to RFC spec on how a header should look.

How should I correctly set the format parameter of text/plain?