[...]I just discovered that messages sent to "tlhingan-hol@stodi.digitalkingdom.org" (rather than the official "tlhIngan-Hol@kli.org" address) are not archived.
I would recommend to check your email client to see if your replies are going to the "tlhIngan-Hol@kli.org" address, and to check your outbox to see if you had been sending messages to "tlhingan-hol@stodi.digitalkingdom.org" instead.
I usually use Thunderbird, and I use the "Reply List" button, because list messages have a header that reads:
List-Post: <mailto:tlhingan-hol@lists.kli.org>
Messages I send, except when I start a thread, therefore go to
tlhingan-hol@lists.kli.org. I manually changed the last couple of
messages I sent, but generally, this is where my messages go.
If this is not correct — you didn't address that one, so I'm not
sure — you may want to change the List-Post header to a better
address.
-- SuStel http://trimboli.name