[Dovecot] sendmail smtp auth using client socket

[EQX]

Hi list
I searched the net, but could not find something related.

Is it possible to export the client socket to sendmail for smtp auth?  
What would be the sendmail.mc configuration for this?

   #client {
      # The client socket is generally safe to export to everyone. Typical use
      # is to export it to your SMTP server so it can do SMTP AUTH lookups
      # using it.
      #path = /var/spool/postfix/private/auth
      #mode = 0660
      #user = postfix
      #group = postfix
    #}

It can also be the other way round: can Dovecot use Cyrus SASL for  
user authentication?

I need to use sendmail, ip based solutions like pop-before-smtp or  
poprelay are not an option.

Thanks, Mike