Can't be done.  Outlook takes an exclusive lock on the file.  You will need
to close Outlook in order to backup the .pst file.  If you are on a
WinNT/2000 platform, you can run St. Bernard Open File Manager which will
allow you to backup the file.

Kelly J. Lipp
Storage Solutions Specialists, Inc.
PO Box 51313
Colorado Springs, CO 80949
lipp AT storsol DOT com or kelly.lipp AT storserver DOT com
www.storsol.com or www.storserver.com
(719)531-5926
Fax: (240)539-7175