Hi markrnaustin, and welcome to the avast forum.
Everything you need to do is configure the ISA provider. To do this, start avast Enhanced Interface (if it starts in the simple (skinned) interface, switch it to the Enhanced UI by using the appropriate menu item), go to the Tasks folder and open Properties of the Resident Protection task.
Scroll to the ISA provider, and customize its settings.
E.g.
- for the provider to scan even text files, go to the Exceptions page. Text/* is by default excluded from scanning
- for the unpackers, see the Archives page.
Thanks
Vlk