Which mail user agents (MUA, written as mua by another poster) properly 
respect the threading that some readers of the SL list require upon 
using an existing email message as an ad hoc form for posting to the list?

This is not a frivolous question -- for example, is this email causing a 
"hijacked thread" or "Change topic or new post..."?

If not, I have found a method that works under Linux Thunderbird 3 
current without a template.  If there is a means to post screenshots, I 
can demonstrate.  If it is not working, back to further experimentation.

Yasha Karant