never tried to do that before, but have you tried these ??
zmmailbox -z -m account@domain search -t appointment "before:10/13/08"
it will get a list for all appointments(Calendar record), something like :
Code:
21. 4137 appo <na> xxx project 07/31/08 16:32
22. 3549 appo <na> xxx visit 07/14/08 16:27
23. 3434 appo <na> xxx 07/10/08 16:21
24. 3421 appo <na> demo 07/09/08 14:46
25. 3288 appo <na> xxx 07/04/08 17:38
and we can take out the ID(that's 3549, 3434, 3421, 3288 in this example), passing to zmmailbox command again:
zmmailbox -z -m account@domain deleteItem <id>
not sure if it helps.