[napo_p2p]

Maybe also try:

//#CLIENTSIDE
if (playerenters) {
  removetiledefs;
  addtiledef2 refino_npulse-tileset.png,refino,0,0;
}

Also, as Stefan said, this is best in a weapon initialization script. But, if you are doing this offline, then that should work. Remember to delete the script before uploading (and make sure you do use a weapon initialization script).