It would be really handy to have a pdf at the end of the each line that shows the invoice or statement or pay advice that has been attached to the email. If the invoice is changed after the time the...
It would be very helpful to be able to view the attachment sent with an email. It would make it easy to verify what exactly has been sent, particularly for other users.
Also, being able to view a copy of the actual invoice as sent (e.g., as a PDF) would also be helpful. Sometimes invoices are modified after they are emailed (e.g., corrections, or customer feedback). Being able to see what was actually emailed in the past ould be useful in solving customer problems/complaints.