I found some info in the manual, maybe theres a workaround here:

Passable:
Obsolete flag, for non-mesh levels only. Makes the block penetrable and its surfaces visible from the inside.

Invisible:
Invisible block. When setting the Invisible = None flag in the map compiler dialog, the block is still used in the BSP tree, can clip away objects behind it, and throws static shadows. Otherwise it's completely invisible for the view and the AABB collision detection.

Detail:
Detail blocks don't affect the BSP tree, as normal blocks do. They can be used for small details in the level, like small pillars, ornaments, rounded arcs or other elements which would otherwise increase the portal count and building time. Because Detail Blocks do not suppress the rendering of the scene behind them, they should not be used for objects that hide much of the level - otherwise they will reduce the frame rate. Do not try using Detail Blocks as level boundaries, and don't let them touch or intersect other blocks. They are ignored by the collision detection.