Calendar Item not display if resource mailbox was not logged on   

I created a few resource mailbox on Exchange 2003 few months ago and didn't 
log on to it.  I set "Auto accept for meeting request".  However, when my 
user send a meeting request, the items does not appear in the resource 
mailbox's calendar.  it will display after I logged on.  Any idea?

date: Tue, 8 Apr 2008 02:23:03 -0700   author:   Joey