Outlook 2010/2013 Exchange calendar sync with Windows Phone 8 EAS Account

I can't get why every kind of sync action in calendar works well but not deleting an item from Outlook (both 2010/2013 version).

The issue is very annoying and Dangerous cause you could have a calendar event that not exist.....

Somebody could help me?

Thanks

Enrico

Interested Platform: Windows 7, Outlook 2010 (2013 tested too) with sync RPC over HTTPS with Exchange 2007