Jim,
Hmm. It's not clear where your confusion lies. However, you may like
to set control/defaulthost (that's normally /var/qmail/control/defaulthost);
here's the section of the qmail-inject man page:
. defaulthost
. Default host name. Default: me, if that is supplied;
. otherwise the literal name defaulthost, which is
. probably not what you want. qmail-inject adds this
. name to any address without a host name. defaulthost
. need not be the current host's name. For example,
. you may prefer that outgoing mail show just your
. domain name.