Microsoft has released an update for Lync for Mac 2011

Improvements that this update provides
This update update provides call control functionality for Optimized for Lync USB audio devices. Microsoft and the OEMs that make USB audio devices have verified that this update qualifies for the Optimized for Lync logo on most devices.

For a list of Optimized for Lync devices that will work best with the Lync for Mac 2011 client, please contact your preferred Lync device partner.

A full list of qualified devices and device makers can be found at the following Microsoft website:

Phones and devices qualified for Microsoft Lync

  Update for Lync for Mac 2011 - KB2778095