What is needed for S/MIME remailer ?

[baldwin (Robert W. Baldwin)]

        The other day I was wondering what it would take to make an
anonymous remailer for an S/MIME client.  Implementing S/MIME from
scratch is a lot of work given the lack of a public domain
implementation, but it seems that a remailer could be built on top
of a commercial email product that supported S/MIME.  The question
is: What features should a commercial S/MIME email product have to
make it easy to support a remailer?  Are there a small set of
command line options that would greatly simplify a remailer
implementation?
                --Bob Baldwin