Zimbra frontend and licencing

Hi

About too publish our zimbra server for external use. And it seems zxmobile could do the trick.
I Have some questions :

zimbra 7.2.2 is not listed as verified for use, This true ? Or will it work ?

our setup:
zimbra Fronted (dmz) : mta
memcached
proxy

zimbra Backend (int dmz) : ldap
mailstore
etc

Will the module work with this setup ? If so Where should the zxmobile module be installed ? Both the servers listed ?
Lisencing is per mailbox, so i guess the number of servers have nothing to say ?

Hope this was understandable.