How to add text to the mail body of ERS Invoices messages?

ERP 4.7

Dear ERS gurus,

I found the thread http://scn.sap.com/thread/1064828 for changing the mail title of ERS e-mails.

BUT:

How to let the mail body also be printed in such an ERS e-mail? No matter what text we maintain in the defined mail text (in NACT --> MR) , the mail body is not printed at all.

An e-mail with pdf attachment and the defined title is sent, but no actual e-mail text will be printed (completely empty mail body).

Thanks a lot for any hints.

Best regards,

Henning