New calender sync after adding Office 365 account

Hi,

I always had one Outlook calendar that I have syncced with my iPhone 3GS.

Now I have added a MS Office 365 account with another calender.

After adding this new account iTunes won't syncc any of two anymore.

No errors occur during sync. In iTunes I can only see one calender. On the iPhone I see both.

Are there any known problems with Office 365 / Exchange?

Thanks for a hint.