I think Precision 2012a has been released because ISE 14.1 now supports it. if you look at ISE's release note, in the external synthesis tool's support, two tools have been supported:
1- Synopsys Synplify/Synplify Pro (F-2012.03-SP1)
2- Mentor Graphics Precision RTL/Plus (2012a)
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more info:
http://www.xilinx.com/support/documentation/sw_manuals/xilinx14_1/irn.pdf