Jeff Macdonald wrote four months ago on the Discuss list:

> The first panel has an interesting participant.

One of the papers was about Sender ID and states:

| Sender ID acquires the sender's domain from
| the SMTP "MAIL FROM" or EHLO command or from
| a message header field determined by the
| Purported Responsible Adress (PRA).

In other words spf2.0/mfrom really is supposed
to be the same as v=spf1, and it's good when
the next Authentication-Results Internet Draft
adds an smtp.helo row to Sender ID, it already
has this for SPF.

 Frank

References:
http://ftc.gov/bcp/workshops/spamsummit/Microsoft-Sender-ID-Framework.pdf
http://tools.ietf.org/html/draft-kucherawy-sender-auth-header-09
--
My reply to spf-discuss run into some mailing list problems,
this attempt is a test.