Under the attributes for a specific document that is uploaded in WP DM, in the Add Custom Field section, there are BNFW options listed. Might this be a way to make this work? Im not sure how to use the Custom Field option, but for BNFW there are options such as:
BNFW_Notification
BNFW_Message
BNFW_Subject
BNFW_Users
BNFW_email_formatting
etc…