You can't import poser hair at all in second life.. you can't import ANY 3d object at all.. items in sl need to be made of primitives (prims).

You COULD import a hair transmap, and apply that to prims in second life, but the uv mapping would have to be similar to the uv maps of the prims in second life for it to work.

While some texture resources could be reused in SL, (think flat square plane based)  most could not.

Way too many people take way too many things way too seriously.