FAR 61.159.a.4

(4) 250 hours of flight time in an airplane as a pilot in command, or as second in command performing the duties of pilot in command while under the supervision of a pilot in command, or any combination thereof

The ONLY time you would be doing this is in 121 is on IOE after your Captain sim check ride. At no time while your an FO are you performing the duties of PIC under the supervision of a PIC. This is known as Supervised Pilot in Commmand. SOme get SPIC during their commercial-multi rating during their required cross country flights but flying SIC in 121 your are not. In order to get the sim check-ride for captain and your temporary airmen certificate you must qualify for it. IE you have to have the 250 hrs PIC or "SPIC" already. Yes ICAO has some say in things, obviously, but on your airmen certificate no where does it say ICAO it says FAA Airmen Certificate.