Have you tried the shapes.xml file?
<shape name="cubeHalf1mHole"> <property name="Path" value="solid" /> <property name="Model" value="cube_half_1m_hole" /> <property name="CustomIcon" value="shapeCubeHalf1mHole" /> <property name="ShapeCategories" value="Square,Round" /> <property name="Collide" value="movement,melee,bullet,arrow,rocket" /> <property name="UseGlobalUV" value="G,L,G,G,G,G" /> <property name="LightOpacity" value="0" /> <property name="WaterFlow" value="permitted" /> </shape>