After sending invoice via email we have two attachments.

The first one comes from print invoice.
The second from the email template.

If i print first and then send a email, we have also two attachments.
The downloaded print file have the name Invoices.pdf

This is user confusion.

1. No print attachment if i only sending email
2. Custom name for print attachment and filename

Print: Invoice_SAJ_2014_0001_.pdf (2)
Filename: Invoice_SAJ_2014_0001_.pdf
Email: Invoice_SAJ_2014_0001_.pdf (1)

How can i configure that?