no, the cfg shall be at the same location like all other variable configs: in the game cfg/sourcemod folder. just let the game generate it for you. that's EASY.
don't know why !rank did not work. for me it did - and I played CS:GO for 3h yesterday. Just check the error logs please. Maybe there's a crash report.
And everythin else fails, please try typing sm_rank or sm_kpd in you developer console and check if the menu appears.