Strange Word/Outlook Interaction

[Dan]

I've written an application which opens Word and then loads an addin (which
I also wrote). I've just noticed that, if you start Outlook after my
application has started, and if you've set Word as your email editor in
Outlook, then Outlook seems to inherit the addin. (I can tell this because
of the toolbar buttons which appear in new email messages). Then, when I
shut down my app, the addin stays loaded in Outlook--which I don't want. So
I tried unloading the addin before exiting my app, which gets rid of the
addin but leads to other strangeness: despite the fact that I've called
application.quit from my code, an empty Word window appears. If I hit
Alt-F11, I find that this window has an "email" template project loaded.
Then, when I close the empty Word window, and close Outlook, I still see
Winword running in the task manager.

So I have several questions:

1. Is there anyway to prevent Outlook from attaching to already running
version of Word?
2. Where is this empty Word window coming from after I exit from my app, and
how can I get rid of it?
3. When I close the empty Word window and close Outlook, why is there still
a Winword running?

Thanks...

Dan