Currently, you cannot. The UI in Outlook will let you edit the name but it won't get synced to our servers and the change of an address books/calendars name will be reverted immediately.
But you can change the name via our webapp:
- Log in on fruux.com and go to contacts or calendars.
- Click the cog wheels next to the item you want to rename from the list on the left.
- Edit the name to your liking and hit save.