Need Help on Statistical Thermodynamics: How do you convert between k ln W and - Sum of Pi ln Pi

[Pennstate]

I am trying to find a proof to link Claude Shannon's informational entropy as defined by
S = - (sum of)Pi ln Pi

with Boltzmann's statistical thermodynamic entropy

S = k ln W.


After looking into 3 p chem books and searching the web, I can't find the conversion. Am I wrong to think they are interchangeable?

 

[Pennstate]

c'mon folks, I know some of you know this