update recurring SharePoint calendar event in Outlook

I use Outlook 2007 SP2 to open a WSS 3.0 SP1 calendar. The calendar contains
recurring events. When I change one occurence of a recurring event in Outlook
(known as creating a recurrence exception), for example by changing the date
of that occurence, the change appears in Outlook but cannot be made to
SharePoint, even after manual synchronization. There is no synchronization
error reported in Outlook.

What's more perplexing is the change sometime may propergate to SharePoint.
But most of the time failed.

Anyone experiencing the problem? Help to troubleshoot is appreciated!