We're lazy and stupid... Now we don't understand this you posted before:
The reverting-to-the-original-version thing you're seeing is a consequence of the fact that deftasks.xml is normal part of avast installation and therefore the avast auto-repair feature always replaces it to the original version. However, this is not a problem as the "import" procedure from the modified version is already done at that moment.
Please, help me on my thought:
1. avast loads
2. the user changes some settings
3. the user runs the repair function and deftasks.xml is 'restored' to original state
4. boot
5. What happens with the configuration?
Between which step the configuration of number 2 was saved?
If I understand correctly, among the configuration stored in deftasks.xml are the archive file types to be scanned 'on-access', aren't they?
On-demmand you can check 'all' archive files to scanned...
How to do it on-access?
See Igor's post:
For the on-access scanner, you are right.
In the on-demand scanner, you can enable all supported packers by the checkbox "Scan archive files".
Can you teach me?
