They can be if 3D World Studio supports BSP. I did originally have a DarkGDK.NET plugin that was designed to load the older Cartography Shop files (.CSM) But Leadwerks now support only 3dws files. I'm aware of another user online here 'Lost In Thought' He had written a plugin for DarkBASIC Professional for loading in 3D World Studio files (similiar work I did with the CSM plugin)
Check out this thread:
http://forum.thegamecreators.com/?m=forum_view&t=119319&b=22
You may be able to get in touch with Lost In Thought and ask if he has done any work on the plugin, and whether it can be moved to DarkGDK.NET.
Paul.