need help with cheats on server.

[bandit]

i cant turn on cheats on my server. i know the command to toggle cheats (sv_cheats 1) but everytime i type it in i get a message that says "sv_cheats is read only". how do i fix this?   

[Lakitu7]

devmap <mapname>

[DraZiLoX]

Open console and write

Code Select Expand

/devmap <mapname>

:p