How do I remove one of the calendars from iCloud but keep it on the iPhone to sync with Outlook by USB and keep the other calendars synced on iCloud ?

iPhone 5, Macs and iPads at home, Windoze7 system at work.

Using iCloud to sync calendars, contacts, etc on all the home devices. Used USB cable to sync at work with the Windows system, with the Outlook 2010 corporate account (corporate server). I need only the Outlook calendar to be synced, syncing the contacts created too many problems with duplication, etc. No need for that. Worked fine until the latest upgrate to iOS7 and iTunes 11.1. Used to have a calendar that was not on iCloud and was simply and exclusively syncing between the iPhone and the Windows computer at work. The other 3 calendars synced fine with the macs and iOS devices via iCloud but not with the machine at work - keeping private records private.

Upon the iOS upgrade, all calendars are now on iCloud. I am no longer able to remove one - for security too - from the iCloud and sync it with the Windows computer exclusively. I managed to sync it once on the PC with iTunes by switching iCloud off on the iPhone before connection by USB cable. Trying it again, it tells me that it will erase all items on the Outlook account (the "more than 25% of your records are going to change" alert) and won't add or modify any. I stopped the sync in time...

Tried on the iCloud site for a solution to remove the calendar, nothing.

There is no iCloud setup on this corporate computer - no access permitted. The USB cable connection is the only solution and up to the upgrade of the iOS this went seamlessly.

Any solution out there?

Thanks

Vladski