From LO Calc to .ics calendar files for Thunderbird

Is there a simple way to achieve this? I don’t want to hand-write a whole batch of dozends of dates into Thunderbird. There must be a way to perform this in Calc…

All I found was this Makro-based approach for Excel - which doesn’t work in LO:

http://www.sunbird-kalender.de/forum/viewtopic.php?f=12&t=3220 (it’s in german)

Here is a Makro from a OpenOffice-Board: http://de.openoffice.info/download/file.php?id=3959 (download)

It is possible to add a column for repetition (Wiederholung)

To the macro (section “writeICS”) I appended to the paragraph " 'optionale Angaben" the following lines:

`'Wiederholung

  s=osheet.getCellByPosition(9, posR).string

  if s<>"" then print #outFile,"RRULE:FREQ=" & Umlaut (s)

`

Now it adds the frequency as written in the additional column (WEEKLY, MONTHLY, YEARLY) to the .ics file.