Zextras Mobile + Blackberry

We are fresh Zimbra users (OSE) for abouth one month and i was looking for some estensions to install (mainly ZeXtras Backup) but this one can be interesting too
Our users use only the webmail but i got two of them with a blackberry reading the mail trough BIS service that don't sync contact or calendar.

On the ZeXtras mobile it's reported as tested device BlackBerry with AstraSync ZxMobile, so mean that for a full working solution i have to pay licences for both (AstraSync + ZxMobile) right?
But ZxMobile could be enough to sync calendar and contacts with an Outlook installation and then to the device trough the BlackBerry desktop software ?

Regards
Davide