Redmine

I have installed Redmine on CentOS 6.2 and we are evaluating it in a small group to see how it could fit into our organization. One of the things we have noticed is that issue update notification emails include:
- a notice that the issue has been updated and by whom
- the text of the update
- the subject of the issue, with a link to it
- a bullet list of the issue parameters and their values (author, status, priority, &c)
- the text of the original issue
Since some of the issue details and updates could contain sensitive information, I would prefer to suppress the details of the issue in the emails, ideally with only an indication of who updated the issue and a link back to the issue. I started editing a copy of app/models/mailer.rb, commenting out line 75:
#:journal => journal,
to see what, if anything, that would change in the email, but I really don't know much Ruby, and it probably shows: that just resulted in a server error with
/var/www/redmine/app/views/mailer/issue_edit.text.erb:1: warning: Object#id will be deprecated; use Object#object_id
in the Apache error log.

Can anyone provide a brief overview of how to control what elements of the issue are put into the email body? Am I even playing with the right file? Is there a plugin or maybe a discussion thread that addresses this sort of thing? Eventually, I'd like to put together a plugin that controls what is or is not included in an email rather than hardcoding the mail handler, but I'll need a much better understanding of Ruby and the Redmine internals before I can accomplish that; right now, I'd settle for an idea of how the email body is built and how to alter it.

Thanks,
ben