Notification message

I am a new user of avast! - it has replaced McAfee. I am very pleased with it and it is working extremely well.
My question is - Whenever I send an Email to a friend I have set avast! for the message to be displayed at the end of my email. It also places an attachment in the subject line on outlook. How do I still keep the message at the bottom yet get rid of the attachment?
A very small question but any help would be most welcome.
David