Hi,
if the demo-exploits on the heise web site are not discovered, I think it is very likely, that other, more threating exploits in the wild are not discovered either.
I doubt, that avast excludes "friendly" exploits which just demonstrate the possibilities. If a demonstration of an exploit is proven by such web sites like the heise web site, it just shows that other exploits may not be discovered by avast or other scanners. At work the mcafee scnner however discoverd the heise demonstration.
Reiner