Camilla Salander (possible spoiler if you haven't read all the Larsson books)

Okay, I just finished Steig Larsson's The Girl Who Kicked the Hornets' Nest.  I was pretty satisfied except for one thing — Camilla Salander, Lisbeth's twin.  What is up with her?  Why is she mentioned here and there and then no more?  With all the attention given to Lisbeth there was nothing done with Camilla? Why does no one seem to care?  Not Blomkvist?  His sister? The baddies?  The goodies?  Let me edit that — why does no one appear to care?  Is she a clumsy red herring?  I have a hard t...