SWAT ELITE FORCE 5.3 MOD GAMERANGER RECOGNITION.

Need specific help. Im trying to set up a coop campaign with my friend in SEF mod thru gameranger, the problem is you can't manually select the exe. in gameranger to SEF exe. It say it's invalid. So the only options are SWAT4.exe and SWAT4 Stetchkov Syndicate.exe. We really need to play the SEF version as it has plenty of technical fixes and is generally more stable. We have the GOG version. Any help would be appreciated.