The Import and Export Plugins for Assetto Corsa have been enhanced to include better support for the KsShaders used by the Assetto Corsa materials.
The FBX Export Plugin has the same improvements for exporting to the KsEditor.
Please follow this link for a short guide to using the KsEditor with FBX exported from 3DSimED3.
Go to the downloads page for the latest version of the Assetto Corsa Export/Import and FBX Export Plugins.