HLSL's still a lil confusing for me...

The hardest thing is converting bewtween coordinates.

Light positions are sent to the shader using world positions, and so are the verticies [using world positioning]. But you have to use the dot() product of the surface normal to get lighting direction. However, the normal isn't so easy to get, as I believe you have to combine the surface "normal and tangent to create a binormal".

Matt should know more about this than I though