[Exim] Exim 4: auth_advertise_hosts

..is not the right option but I couldn't think of a better subject..

I want to advertise STARTTLS everywhere, and only when the client has
successfully done this do I want to advertise AUTH. Can I do this?

I thought this was the behaviour I had with Exim 3, but I don't want to
switch back just yet to find out for sure as having just migrated to 4.01
I think this is one of only two oustanding issues that have cropped up.
(The other, if I don't resolve it, will appear in a separate mail. :)

Cheers,

Matt