Hallo,
Why are you so keen to check outgoing mail? If Avast!4 is keeping your PC free of viruses its not necessary in my opinion to check outgoing mail.
I know that almost most anti virus programs do this check, but in my opinion it is a needless operation. I think that long time ago a manufacturer of anti virus programs wanted to distinguish his program and added this feature. His competitors could not stay behind and so this fairy-tale became a standard part of anti virus software. In my opinion, as I wrote above, indeed a fairy-tale. If your PC is free of any virus how could you sent a virus with your e-mail. Besides that almost most viruses are distributed via attachments to e-mail and those attachments are almost most executable files (.exe). I think that a good virus scan program as Avast! 4 on the receiving PC is the only necessary operation.
More important are the so called worms. They can spread out all over the world without active actions of the PC user. However you can partly block a worm to use your address book by both the first and the last address in your e-mail address book making fakes with a name in the address book but without an e-mail address to that name. If the worm wants to start his sending operation, either from A to Z or from Z to A, to the e-mail addresses in your address book if discovers a failure and stops. I don’t know if newer worms can handle this but for some time ago it was an pretty reliable way to block worms to uses your PC to spread out over the world.
If the Avast people don’t agree with me I’d liked to learn about.
Jan