I posted this on Stack Overflow also: http://stackoverflow.com/questions/34804072/auto-add-document-to-docusign-salesforce-using-custom-button

I'm using a DocuSign custom button. I have the document Id of the document I want added into docusign, on my object. Is there a way to automatically add the document using that Id?

The use case is, I'd like my user to hit the send via docusign button, and already have the document and the docusign envelop configured. Currently they have to search for the document, because it's not related to the source record and not in notes and attachments.