So, in the end I appropriated one material with "q3map_material SolidMetal" I used for render geometry and made it invisible in blend stage of the shader especially for collision mesh. Not very pretty I imagine, but it works. In this way spawnflags 2 worked as well.
I uploaded the map and I'm waiting for approval. I'm open to suggestions to improve it, so please let me know. I included .map and .ase files as well...