Attach files with Document Transmittal?


We're currently auto-sending invoices via email through document transmittal.  I'd love to be able to attach additional documentation (remittance instructions, W-9, credit card auth form, etc.) with the invoices that are sent via email.  However, it doesn't appear this is possible in Sage 500.  Is there a way to attach additional documentation in document transmittal (or elsewhere) that will go out with our invoices when they are emailed?  The only thing I can think of is I'll have to turn off auto-send to have the invoices go to a specified Outlook folder and then manually attach from there before sending. Thoughts? Ideas?