TODOs are not correctly synced to my CalDAV (owncloud) account throught meego's builtin app.
If I create a TODO with the N9, it will appear on owncloud and be synced correctly.
If I create a TODO from elsewhere (I tried with owncloud's web interface and gnome's evolution), the N9 will never show them.
To sum up, the N9 will only show the TODOs that have been created using it.

Anyone else experienced this ? Is this the standard behaviour ? Can it be changed ?
Should I try to use syncevolution instead of Meego's builtin CalDAV sync ?

Same here using radicale hosted in my server.

syncevolution works with tasks together with the N9 and owncloud 5.

The backend is CalDAVTodo. You can have one todo-entry in syncevolution for each available calendar.

You have to use the newest syncevolution version 1.3

https://openrepos.net/content/holgern/syncevolution
or
http://people.debian.org/~ovek/harmattan/

You can find more infos here: http://www.nrtm.org/index.php/2013/01/09/4144/

This site is in german, but you can use google translate. I was able to configure my N9 using this site.

The following site was also usefull:
http://tanghus.net/2012/07/syncing-y...oud-an-update/