Outlook/iPhone calendar not in sync

[richardyu301]

I have just switched from Windows to Mac and bought a MBA 13".

After installing Outlook 2011 (EAS), I tried to sync the iPhone and Outlook calendars. However, I found that:
i) all events previously entered in Outlook are shown correctly on iPhone
ii) all events previously entered in iPhone are delayed 6 hours in Outlook

I have tried to enter some new events, it turned out that:
i) new events entered in Outlook are shown correctly on iPhone
ii) new events entered in iPhone are delayed 6 hours in Outlook

My iPhone settings are as follows:
i) General -> Date&Time->Set Automatically: have tried both ON/Off but no difference
ii) Mail/Contact/Calendar->Time Zone Support: have tried both On/Off but no difference

My Mac settings are as follows:
i) System Preferences->Date&Time->Time Zone->set time zone automatically using current location: have tried both ON/OFF but no difference
ii) Outlook Preferences->Calendar->Default time zone for new events: have tried both ON/OFF but no difference

Can someone help???

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BTW, time zone of Hong Kong is UTC+8.

thank you