Dynamic Stamp including drop-down list

You can't do this directly. Dynamic stamps are not interactive. The fields are just for displaying info. When it's stamped on the PDF it's flattened out.

You can however add a custom dialog to the dynamic stamp on which there is a drop-down. See this article.

[url=http://www.acrobatusers.com/tutorials/2007/dynamic_stamp_secrets/]http://www.acrobatusers.com/tutorials/2007/dynamic_stamp_secrets/[/url]

I have a similar but slightly different problem: I need to apply a pre-formatted template/text box to a PDF document that's allows a downstream recipient to add invoice coding information in the prescribed fileds...any suggestions?

See this article:

http://www.acrobatusers.com/tutorials/2007/js_add_buttons_to_pdf/

Text fields can be added to documents just as easily. You can even create a toolbar button to do it. See this artical for some information on building a toolbar button:

http://www.acrobatusers.com/tutorials/2007/10/apply_security_with_js/

You also might want to take a look at this 3rd party tool that automates creating toolbar buttons and even includes demo code for adding text fields to a document.

http://www.windjack.com/products/acrobuttons.php

Thom Parker
The source for PDF Scripting Info
[url=http://www.pdfScripting.com]pdfscripting.com[/url]

The Acrobat JavaScript Reference, Use it Early and Often
[url=http://www.adobe.com/devnet/acrobat/]http://www.adobe.com/devnet/acrobat/[/url]