The field "Tools" -> "Preferences" -> "Buldozer" -> "Data directory" seems to be ignored by Terrain Builder and Buldozer. The directory of the Buldozer.exe (Arma3.exe) is always used as working directory.
In V3 we were able to specify a Buldozer-path and a Buldozer working dir. So we were able to use the arma3.exe and path (including all .dlls) as Buldozer executable but let it use the P: folder as working dir for loading textures and objects.
Without this we have to either copy the whole Arma3.exe and Dll over to our working dir or we have to copy our projects to our ArmA3 dir. {F23549} {F23550} {F23551}