After upgrade to pre-4.5.7, I have some issues with the connector (see :
Bug 18408 - Build 1068 ZCO does not like full names for recipients).
I followed this thread and my "sharing extension" was disabled by Outlook (Help, About, Disabled items).
So I re-enabled it.
A couple of Outlook restart (one in "safe mode") and it's now fully working 8)