On my shared hosting I setup a zencart using just sendmail-f, the program would send out emails to whatever addresses specified. This doesn't appear to work under plesk. I see that Qmail is installed under /var/qmail. However it doesn't seem to work.

Does anyone have any experience, or ideas on this one?

Hi,

Just for all interested in this matter, properly installed Qmail supports the sendmail binary and path to it will be the same as if Sendmail server is installed.  Usually, it is /usr/sbin/sendmail.