Forefront Security for OCS now supports Lync 2010 servers, with the latest hotfix rollup 4.
Hotfix Rollup 4 allows FSOCS to be installed on Lync 2010 (running on Windows 2008 R2 or Windows 2008 SP2 x64) in addition to OCS 2007 and 2007 R2. As the feature set and patch level are the same as RU3, customers who have already deployed RU3 can update, but are not required to do so.
The hotfix has to be requested and downloaded.
Get rollup 4 here