I have a mixed enviroment , one domain managed by exchange and one manged by zimbra, all works fine from an interoperability point of view (mail exchange, gal , appointemnts created with partecipant in both domains etc ...) the only thing that is missing is the possibility of checking the free/busy status between domains.

I've read in the online help that free/busy infromation is available only between zimbra and exchange 2003-2007.

What ca I do to make available this information to outlook/exchange users ?