Something like the following should work:
Code:
/opt/zimbra/bin/zmprov
prov> sm user2@macpro.local
mailbox: user2@macpro.local, size: 7.88 KB, messages: 2, unread: 2
mbox user2@macpro.local> createFolder --view appointment --color blue --flags "#" /Calendar2
259
mbox user2@macpro.local> postRestUrl /Calendar2 /tmp/cal.ics
mbox user2@macpro.local> exit
prov> exit
The "--view" arg specifies that it is a calendar folder, and the "--flags" arg with "#" means it will be checked by default in the UI.
The CreateFolder docs in soap.txt are a good place to poke around in.