First off, download this prefab:
http://twhl.co.za/mapvault_map.php?id=4128
EDIT: Link is fixed and hosted here
Now, place said prefab here in this directory in your Steam folder:
sourcesdk/bin/Prefabs HL2/Prefabs
Now, open hammer. place the prefab somewhere in the map (anywhere, just make it out of sight) and compile. (it looks like a 3D letter "T" thats orange)
Remember, do NOT rotate, or even translate the object. Use the entity tool to place it accurately on the grid, then go to "Create Prefab".
Now, try to decompile the .BSP. You will find that it does not work! Thats it
![:)](http://192.241.182.11/images/smilies/smile.png)
![:)](http://192.241.182.11/images/smilies/smile.png)