For users of Kontact, it's possible to work in interactive mode: when you modify a contact your Memotoo address book is updated directly (and vice-versa).
Copy this address in "Remote Server URL" when you create the calendar in the application: Install the package "kdepim-kresources" to have the option "calenderar in remote file".
If you choose "GroupDAV server (e.g. OpenGroupware)", enter this address in "URL":