I doubt if a newer firmware has been released which starts supporting this feature yet..Version 1.08 was released in September and the release notes doesnt seem to indicate anything...
http://www.cisco.com/en/US/products/hw/phones/ps379/products_qanda_item09186a00801a22f1.shtml --- FAQ
http://www.cisco.com/en/US/products/hw/phones/ps379/prod_release_notes_list.html ---Version 1.08 Rnotes
The status of this feature request to add corporate directory seem to be in a CLOSED status. Here is a link to the Feature request ID.
http://www.cisco.com/cgi-bin/Support/Bugtool/onebug.pl?bugid=CSCea08607
CLOSED status is described by Cisco as follows - "Bug report is valid, but a conscious decision has been made not to fix it at all or in all releases. Normally, a development engineering manager moves a bug report to this state. This state is not available in all projects."
Sankar Nair
UC Solutions Architect
Pacific Northwest | CDW
CCIE Collaboration #17135 Emeritus