she has no gmail nor does this answer my question in any way. or i dont understand what you mean.
she has a 3rd party email provider that is not listed in the IPDB of thunderbird , because the smtp/imap server are public ones, but her domain of course is not, so autodiscovery via IPDB does not work.
the only way to configure the clients automatically is to use such .xml in the file directory as described here http://www.pscs.co.uk/manual/mozilla-thunderbird-autodiscov.html
But to do so, i must add the .xml to exactly that location.
If the router can be configured to listen for exactly that location and i can read the .xml and provide it as stream, i could imagine that this works too. But i dont want to spend ours in reading how wix routers work, if my goal is not possible with that.