[R-sig-ME] Edward's 2008 R^2 for lme?

[Etienne Laliberté]

Without wanting to start a heated debate on the pitfalls associated with
a "R^2-like" statistic for linear mixed models, I would simply like to
know if someone happens to have implemented Edward's 2008 approach in R
for lme(), and if so, if that person would be willing to kindly share
some code.

Edwards, L. J., K. E. Muller, R. D. Wolfinger, B. F. Qaqish, and O.
Schabenberger. 2008. An R2 statistic for fixed effects in the linear
mixed model. Statistics in Medicine 27:6137-6157.

Thanks,

Etienne