Modded game file to stop despawning of both bodies and objects. (Including dropped weapons.)
Go to the "Config" folder in your Strike Force installation and move "Juego.cfg" to another folder.
Replace it with the included "Juego.cfg" file.
This may cause issues in stealth missions since enemy bodies won't despawn so I recommend either moving the edited Juego file or editing it back:
The Juego file included is already decoded but you can download the fan-tool to manually decode the Juego file (and others) from here:
Forums.revora.net
Open a decoded Juego file (either the included one or one you decoded yourself) and search for:
".fDuracionMuertos" and change the number after it to a number of your choosing to change how fast bodies fade.
".fDuracionObjetos" for if you want to change how fast items despawn.
By default both are 30 seconds but this mod changes them to 999 seconds.
Thanks to Herbert and the other Commandos modders at Commandos HQ forums for making this possible.
EDIT: Corrected the download, in my initial download I accidently zipped the wrong file.