Yes, this is a known issue. You can use multiple BES servers against a single Zimbra instance to get around this. You can also disable GAL lookups on the device and make it work that way, though I am not sure if Zimbra will support that if you do. So use the following at your own risk:
To disable the Global Address Book Lookup feature, complete the following
steps on the BES server:
Then the BES admin has to be in its own domain where the entire GAL is available.
1. On the BlackBerry Enterprise Server, go to Administrative Tools, double-click Services, and stop the BlackBerry Enterprise Server <server_name> Service.
2. Open the Registry Editor by clicking Start > Run. Type regedit, then click OK.
3. For BlackBerry Enterprise Server 3.5 and 3.6, go to HKEY_LOCAL_MACHINE\Software\Research In Motion\BlackBerry Enterprise Server\Servers
For BlackBerry Enterprise Server 4.0 and 4.1, go to
HKEY_LOCAL_MACHINE\Software\Research In Motion\BlackBerry Enterprise Server
4. Depending on your BlackBerry Enterprise Server version, right-click either the <BlackBerry_ Enterprise_Server_name> registry key or the Agents registry key, then click New > DWORD Value.
5. Type AllowAddressLookup as the name of the new DWORD Value, then press ENTER.
6. Double-click AllowAddressLookup.
7. In the Value data field, type 0, then click OK.
8. Close the Registry Editor, then restart the BlackBerry Enterprise Server.
On the Zimbra Server:
1. Create a domain with search base set to ROOT for search and sync
2. Create an admin account in the domain:
zmprov cd gal.example.com zimbraGalInternalSearchBase ROOT zimbraGalSyncInternalSearchBase ROOT
3. Auth to Zimbra as email@example.com and GAL search/sync will return entries in all domains.
zmprov ca firstname.lastname@example.org test123 zimbraIsAdminAccount TRUE
Again, I do not know if Zimbra will support you with this, so please use at your own risk. And remember the Blackberry connector is in beta at this point. They may address this in the final release, so you may just want to wait until that happens. And to answer the next question, it will be out when it is ready.