Zimbra + Evolution + calDAV

[snoopy_1978]

Hi everybody,

I'm trying to connect Evolution under Ubuntu 9.04 to a Zimbra Server CE 6.0.1. In Zimbra https encryption is enabled.
When defining a new Calendar in Evolution using the "caldav" protocol with an address like this:

caldav://server/dav/user/calendar

the existing calendar data are read and displayed correctly. But trying to add a new entry Evolution just sais "Unknown error" after clicking "save" and does not save the entry.

Thunderbird/Lightning just work fine with caldav.

Any idea?

Thx a lot
snoopy_1978