Hello,
LUA 2.3 is now available in the SEP 12.1 RU1 MP1 TOOLS DVD under ....\Tools\LiveUpdate
You can download the Latest Version from: https://fileconnect.symantec.com/
You could also get the LUA 2.3 Utility by creating a Case with Symantec Technical Support.
create a Case OR contact Symantec Technical Support.
QuickStart Guide - Create and Manage Support Cases in SymWISE
http://www.symantec.com/docs/HOWTO31132
How to update a support case and upload diagnostic files with MySupport
http://www.symantec.com/docs/TECH71023
OR
Regional Support Telephone Numbers:
United States: https://support.broadcom.com (407-357-7600 from outside the United States)
Australia: 1300 365510 (+61 2 8220 7111 from outside Australia)
United Kingdom: +44 (0) 870 606 6000
Additional contact numbers: http://www.symantec.com/business/support/contact_techsupp_static.jsp
Hope that helps!!