Hi,
There is an utility, called "Simple Process Termination" by System Safety.
You can download it here:
http://syssafety.com/leaktests.html.
It could terminate ashDisp.exe, ashMaiSv.exe, ashServ.exe and ashUpdSv.exe with:
9 - terminate process as a task;
15 - simulation of normal process exit;
and
16 - terminate process by "bruteforce" message posting;
Moreover, I can stop avast! service by stopping manually ("Administrating Tools"->"Services") or with any program for starting/stopping services.
I hope, You'll fix it.
PS
My farewall passed this test. None of 16 methods could terminate its processes or services. When I go to "Administrating Tools"->"Services", I cannot manually stop it. The same thing was when I used Kaspersky Antivirus. I couldn't stop it anyhow, except of choosing item "Exit" in its menu.
Thanks!