Here's a loadout that gives you an M16, 4 magazines, binoculars, 2 grenades, a LAW launcher and 2 LAWs. Hopefully you can see how it works from this. You may be getting a crash if you add more things than the unit can carry.
Copy this into the unit's init line:
RemoveAllWeapons this; this AddMagazine "M16";this AddMagazine "M16";this AddMagazine "M16";this AddMagazine "M16";this AddWeapon "M16";this SelectWeapon "M16";this AddMagazine "LAWLauncher"; AddMagazine "LAWLauncher";this AddWeapon "LAWLauncher";this AddMagazine "HandGrenade";this AddMagazine "HandGrenade";this AddWeapon "Binocular"