I´d like to have this solved too.
Other game from frogwares called dracula origins suffered from the same problem and it was worse because it is a third person adventure and the effect was very ugly and low quality due to te lack of shadows on the terrain.
I solved it using a wrapper, I do not remember the name but it was a dll pack, choosing d3d9.dll, wined3d.dll and libwine.dll. It is used to solve prolems in infinity games (baldur gate etc...) If I am not wong.
I tried the dlls in the holmes games, no luck. But its is worth a try in later versions, the wrapper use to be updated.
EDIT the link to the wrapper https://fdossena.com/?p=wined3d/index.frag