Context Toolbar Change

Is there any way to change the context toolbar that appears below the main
toolbar in the CLIENT.WINDOW.BROWSE toolbar? Not the one with Address Book,
New Mail, etc., but the one with the Delete Icon and Reply and Forward, etc.
It changes as you select different items in the mailbox, so where would that
be?

I am making a spam plugin and already have my commands activate from context
menus and from inside the mail window, but would like it in the context
toolbar as well.

Thanks!