Problems editing SkyDrive docs offline with Office 2013

I've always used SkyDrive in the past (not SkyDrive Pro) to sync my personal docs across my computers, tablet, phone etc.  I use the desktop client which acts just as a folder on my PC.  In the past I have been able to use my laptop offline to edit docs in the skydrive folder on my PC (just as if they were local files), and then when online again it would automatically sync the changes and I would have access to the updated files across the web and other PCs.  This was with Office 2007.

I recently however got Office 2013 on a new machine running windows 8.  I've got the skydrive desktop client on the laptop, but when I work on a file in skydrive while offline, when I save and exit I always get asked by the Upload Centre: would I like to 'discard changes' or save to a different location on the harddrive.  If I 'discard changes' then when I reconnect to the internet, my edits are lost.  However, strangely, if I create a new file while offline, save to skydrive and exit, and select 'discard changes', the new file does seem to sync to skydrive and hence across my devices.

The upshot is:  with Office 2013 and SkyDrive desktop client, I can create docs offline which will sync, but cannot edit docs offline to sync.

This was not a problem with Office 2007.  If it is an issue with the Upload Centre I would be happy to disable or remove it if there is a way.

Thank you for your help.