CalDav with Thunderbird, can't modify event

[TArpi]

Hello,

Sys: Ubuntu: 10.10, OERP : latest trunk, Thunderbird: 3.1.10, Lightning 1.0b.2

I set up CalDav according to the documentation http://doc.openerp.com/v6.0/book/7/7_20_Caldav/index.html?highlight=caldav.
I can see in Tb the meetings from OERP. I can add new meeting in Oerp and TB too.

But I can't modify any meeting in TB , only in OERP.
I mean if I added a new meeting in TB and I want to modify I can't anymore. If an event gives me a reminder (alarm) I can't dismiss, because of this error.

It gives me the following error:

An error occurred when writing to the calendar Oerp_meeting!
Error code: MODIFICATION_FAILED
Description:

In the server's log I see this :

[2011-05-05 12:21:28,454][v602_demo] ERROR:db.cursor:Programming error: multiple assignments to same column "write_date"
, in query update crm_meeting set "edit_all"=%s,"description"=%s,"date_deadline"=%s,"date"=%s,"vtimezone"=%s,"location"=%s,"recurrent_id"=%s,"class"=%s,"state"=%s,"base_calendar_url"=%s,"exdate"=%s,"write_date"=%s,"exrule"=%s,"base_calendar_alarm_id"=%s,"organizer"=%s,"duration"=%s,"name"=%s,write_uid=%s,write_date=now() where id IN %s

[2011-05-05 12:21:28,455][v602_demo] WARNING:webdav:Cannot save 28.ics: multiple assignments to same column "write_date"

[2011-05-05 12:21:28,455][v602_demo] WARNING:webdav:Cannot PUT to http://192.168.0.140:8069/v602_demo/calendars/users/admin/c/Meetings/28.ics: Operation failed

Thank you!

Arpi