Third order solution with skewed shocks

Hi,
I’m trying to study an economy subject to a skewed-normal shock using the “unstable-8” version of Dynare (with skew e=-0.99 in the shocks block).
It occurred to me that there is not equivalent of ghs2 (a ghs3) for the shift due to skewed innovations.
It seems to me that it is not embedded in g_0 either. Skewed innovations would in general imply an additional shifter.
Am I looking in the wrong places?
Thanks and best,
Gianni