I want to modify Excel files on my Android phone, and upload the changed file back to Skydrive.  I can't seem to find a way to do this.  I can open the file in Kingsoft Office easily enough, either directly from the Skydrive app or after downloading it to the Skydrive folder on my SD card, but I can't get the modified version back up to Skydrive, after trying everything I can think of.  On my Windows PC (with Skydrive application installed) if I modify a file in the Skydrive folder it's automatically synchronised to Skydrive, but on Android it doesn't seem to be.  What can I do to make this happen?