lucy24 - 8:16 am on Sep 2, 2012 (gmt 0)
For details, see this page
... which someone, quite possibly yourself, has already pointed me to in the recent past. I think I even looked at it.
Oh well. I did manage to get chummy with mod_expires yesterday. Only took about seven tries-- and NO pleas for help-- to hit on the right wording for what I wanted to do.