I believe that that has largely been superseded by Murphy & Topel, "Estimation and Inference in Two Step Econometric Models",
JBES, 1985, pp 370-379. A quick read through Pagan would seem to indicate that all of his cases are special cases of Murphy & Topel. An example of the latter is
with data file
This is from Greene's 6th edition. The corresponding section in Greene's 5th is section 17.7. This is a bit more complicated than a two-step linear estimation since the first step is a logit, but since the gradient for the logit likelihood is only the density x the regressors, it's not that much different.