Habe jetzt nur ein wenig gegoogelt und was ich zur Header-Manipulation bei Qmail gelesen klingt wenig hoffnungsvoll:
"So what are the advantages of sendmail at all? sendmail isn't just an MTA, it implements a general purpose internetwork mail routing facility under the UNIX(R) operating system. (quoted from SENDMAIL: INSTALLATION AND OPERATION GUIDE ). If you don't need these features, then you are probably better off with qmail. If you need to do special header rewriting, mail routing, or something similar, you probably should use sendmail."