[R-sig-ME] eta-squared in lmer

[Petar Milin]

Hello ALL!
Until now I have never been asked to provide (partial) eta-squared for 
any of my lmer models. However, reviewers in a journal where I plan to 
submit have strict policy of having this particular statistics. I know 
about EZ package, and that it could/should do something of the kind, but 
I do not know details. Please, can anyone tell me how can I get etas 
from typical lmer model? I know general logic of it, but never dig 
deeper. Moreover, I think I've read somewhere that it is biased. Can you 
suggest some good reference?

Thanks,
PM