How to set content_transfer_encoding to something other than quoted-printable?

Hi all,

How do I set the content_transfer_encoding for mail with actionmailer
to something other than quoted-printable? It's a setting with TMail
which action mailer relies on in rails 2.3.*. I am trying to set it to

I have tried:
- mail =; mail.transfer_encoding = "utf8";
- setting the @header["Content-Transfer-Encoding"] in the mailer's
delivery method
- various combinations of ActionMailer::Base.transfer_encoding = ,
content_transfer_encoding =, [:content_transfer_encoding], etc
- all kinds of other craziness with encoding/decoding attempts

There is a comment here that there is a setting in the docs:, but I cannot find it.

Anyone have any ideas? Anything is welcome. This one I've been stuck
on for 5 hours now.