I am wanting to automate sending emails of our invoices to our customers. I understand the premise of the workflow send email action; however, I need to select 1 of 2 documents in the files sublist to attach to the email. The file that needs to be attached is uniquely named {tranid}.pdf and combines the SO and Invoice into 1 .pdf file. I have tried to set a custom field to reference the document, but I can't pull in the hyperlink into that field. I also don't have an option to select the file I want