I found that you can change the signature part of the Email using E-Mail Setup to what you need.   However, if you change  the subject or body,  mailing becomes a hit or miss deal.  
 
So, at our plant some personnel have a meaningful subject line and some don't.
 
When it does not work, it always sends out the PDF not found error message.   It puts the PDF in the installation directory, rather than the one specified.