Same difference, different day.
Multisample is a type of FSAA as is Super Sampling. You then have different flavours such as Rotating Grids, Ordered Grids these are different techniques used for FSAA. AFAIK Deferred rendering (which this game uses) only supports shader FSAA (win all) or MultiSample FSAA under D3D10 conditions I belive the technical term is a floating point sample "hack", but I am not sure and don't feel like looking it up. The Unreal Engine elected to use Multisample FSAA using this "hack", the requirement of which is a Direct3D 10 Environment (Vista/7 + D3D10 GPU) however the game itself uses DirectX9 shaders (SM3)
John