I found a thread in Google Groups that addresses that issue (this is one line):
http://groups-beta.google.com/group/comp.databases.ms-access/browse_frm/thread/73f58e91edbfab7c/5ae61421c28c2418?q=access+report+header+max+min&rnum=1&hl=en#5ae61421c28c2418

Look at the last two posts on the thread.

Hope this helps....