[Exim] vbs virii and system filters and such

I had a question about the most excellently written
anti-mircro$oft system executable filter.

Is it just me, or does this only block these attatchments
if they come from a Microsoft MUA?

If one wanted to make it work for everyone's version of
MIME, how much effort would that be?

--
Dan Kappus, http://www.photobooks.com/~danka