when i set up my map properties and i wrote "rust_" in cl_skyname log

but i get only some default or something ( blue sky and canyons )

1. are you sure you don't have a typo like an extra space in front or behind it in the hammer map properties (cl_skyname)
2. do you have ns_rust installed?
3. are you compiling your map into the nsp folder (beta ns folder without ns_rust)?

3 -->

\Steam\SteamApps\>>your account<<\half-life\nsp\maps

instead of

\Steam\SteamApps\>>your account<<\half-life\ns\maps

Also check the environment/sky tga files exist, location "\half-life\ns\gfx\env"

i don't use STEAM !!

Well the things I posted also count for none steam versions ^________^