or u could use a script and execute it through the Init feild of a ammo crate/box ;;
Example ;D
_crate = _this Select 0
ClearMagazineCargo _crate
ClearWeaponCargo _crate
_crate AddWeaponCargo ["G36A", 5]
_crate AddWeaponCargo ["Steyr", 5]
_crate AddWeaponCargo ["M21", 5]
_crate AddMagazineCargo ["SteyrMag", 25]
_crate AddMagazineCargo ["M21", 25]
_crate AddMagazineCargo ["G36AMag", 25]
Exit
the syntax for the ammo crate's init feild would be
[this] exec "turversammocrate.sqs"
NOTE - u have to name the file "turversammocrate" ;D
Hope that helps
Rhys