It can be done with a bit of registry twiddling (at this point I should give the usual warning about how one can break things horribly by incorrectly modifying the registry, yada yada). I never thought that anyone would want this, so I didn't include the
checkbox.
The forward and reply-all checkboxes do nothing more than set values in the registry, in the HKCU\Software\Microsoft Research Ltd\NoReplyAddin key - for example, if you check the reply-all button, and then examine that key, you'll see a value "Reply
to All" in there with the value 1; if you uncheck it, and refresh RegEdit, you'll see a 0. It so happens that the missing reply checkbox would set/reset a value called "Reply" in the same place. The quickest way to disable reply, then, is check
the reply-all box, then use RegEdit to rename "Reply to All" to just "Reply" such that it'll be picked up by the bit of the code which creates email, etc. To turn it off (ie, to re-enable replying) either delete the value, or change it
from 1 to 0.
Having said that, I'm a bit unclear about what you're seeking to achieve: if you want no replies, the usual technique is to change the reply-to address in your email to some ignored address that just swallows returned emails (you're bound to have seen emails
with "from" addresses like donotreply@somewhere.com. That has the advantage that it doesn't require that everyone is specifically using desktop Outlook as their email client and that all users are on the same Exchange farm.
And please do bear in mind that this add-in is extremely poor protection against email misuse: it's a very low hurdle for someone to overcome - eg, all you need to do is create a new message and copy & paste the contents of the original into it, and
then you can do whatever you want. If you want reliably protection, you probably ought to be looking at things like
Exchange's IRM mechanisms.
