As I was getting ready to post this, I was able to answer my own question. In accordance with general StackExchange etiquette I've decided to post it anyways in hopes that someone else who runs into this problem might find this in the future, possibly after running into the same issues with sources that I did. I've decided to answer it immediately so that no one wastes time on it since the solution isn't interesting.
(†) is wrong, because the paper linked to in the discussion was using a different parametrization of the Wishart; this wasn't noticed by the discussants. What we should actually have is
|Λ||Ψ|∼χ2νχ2ν−1⋯χ2ν−D+1.(††)
After this correction, the two formulas lead to the same answer.
At any rate, I think think (††) is an interesting relationship.
EDIT:
Following probabilisticlogic's advice we can write Λ=dΨ1/2LLTΨ1/2 where lower triangular L has N(0,1) elements off the diagonal and χ2ν−i+1−−−−−√,(i=1,...,D) elements on the diagonal. Taking the determinent of both sides gives (††) immediately.