How to add text to the body of email (Invoice emailing)

Hi,

How to add standard text (constant for all invoices) to the body of the invoice email sent to the customer? I added text in the 'Mail title and text' section of transation NACE, but it is not working. I'm using transaction VF31 to email the invoice. The invoice is sent as a pdf attachment, but the body of email is blank.

Please let me know.

Thanks & Regards,

Ani