acrobat xi -- how can I add a text box to the toolbar and use its contents as part of a dynamic stamp?

I'm working on a project to process incoming PDFs.  I've created a dynamic stamp but the users need to be able to include another value in the stamp that's not an Identity property.  I'd like to add a text box to the Acrobat Toolbar area and be able to reference its content in the stamp.

So:

1) How can I add a text box to the toolbar area?

2) How can I reference the text box's content from the stamp's javascript?

Thanks,

Christian Bahnsen