for qpsmtpd dev relating question you might have better chance actually asking to the qpsmtpd community.
Most people here are using it without knowing they do.
Few people are aware that they use it and are able to play a little with plugin config.
Less than a handfull are able to fix small issues in the code of plugins. And less than that have actually coded a plugin. Not that it is a hard task, just you have to read the doc to do it
.
What you have to know is that it is not because qpsmpd check the plugins that it will actually use them, it depends on the config specific to the network.
Here is where i can help.
first you shall not play in the /etc/e-smith/templates.
this is for rpms. you should use /etc/e-smith/templates-custom.
then you have to ask: do i want only horde /zimbra users to use the plugin or all users ?
if all users you need to configure both for sqpsmtpd and qpsmtpd.
the. do you want only user of the lan or users whatever the network to use it ?
the intended config are
/var/service/qpsmtpd/config/peers/0
/var/service/qpsmtpd/config/peers/local
/var/service/sqpsmtpd/config/peers/0
/var/service/sqpsmtpd/config/peers/local
their templates are in
/etc/e-smith/templates/var/service/sqpsmtpd/config/peers/local/
and
/etc/e-smith/templates/var/service/sqpsmtpd/config/peers/0/
so you have to do
mkdir -p /etc/e-smith/templates-custom/var/service/sqpsmtpd/config/peers/0/ /etc/e-smith/templates-custom/var/service/sqpsmtpd/config/peers/local /etc/e-smith/templates-custom/var/service/sqpsmtpd/config/plugins
and then either put it in 0 or local dir or in the plugins one with link to it in both local and 0.
then
signal-event email-update should do