I would like to make a NAL app that can modify a property of an NDS object
(similar to the way we select and modify a registry setting or a line in a
text file).

Specifically, I want to write some text into the workstation object property
called "zenimgImage" and change the value of the property "zenimgImageFlag".

Can a NAL app do this? Or does anyone have some ideas about how to do this?
If the answer is "do it with LDAP" then I'm lost as to how to get started
writing an LDAP app.

I think that it would be useful to have nal apps working off triggers that
we set in the edirectory. Like show this app only if a certain NDS property
value is set. Or after a successful run we update a status flag in the edir.
It doesn't seem that much different than changing registry settings.