@ DevGru: Add an entry to controls.lst. It's a normal text file which can be opened with a text editor just like the cfg files.
format:
1
"cs2d command(s)"			"description"
Those $XYZ descriptions are references to the language files.
This way you can assign a key for your custom command in the controls menu and the bind will never get lost.
Also note that F1 is already in use by default (opens server info window)!
I tried to spawn objects and items in the startround_prespawn hook. The objects and items got spawned, but they were invisible. I am not sure if this is a bug or a feature? Invisible mines can be quite exciting.
You shouldn't do this in the startround_prespawn hook then. It's clearly not an intended feature and it probably causes even more critical problems. It's a special case which is not handled properly. I should forbid spawning stuff in this hook maybe or try to handle this cases properly.