I'm trying Zimbra in demo hosted suite.

I received the first email, with configuration instructions.

I have set the iPhone and it works perfectly: i created an exchange account.
Everything is in push, awesome. Mail, contacts, calendar, simply perfect.

Then i tried to set the same things on the Mac.
I tried to se the account as exchange too. But it didn't worked. It wasn't able to connect.
Then i tried to set it as CalDav and it worked.
Problem is that if it works as CalDav it hasn't the "total" push. I mean that when i change something from the Mac, it goes over the air just 1 second after.
When i change something on iPhone or on the web, it goes over the air 1 second after, but not to Mac. It'll be synced only after the normal refresh time.

Do you know why i can't set as exchange on the Mac.
What is my error? Thanks!