[Jakku]

Follow these steps:

1. Go to your server
2. Get a vehicle
3. Drive to a place where you want to add a vehicle
4. Type /save when you are inside a vehicle
5. Quit the game
6. Go to your GTA San Andreas folder
7. If you are running Windows Vista / 7, you probably must hit "Compatibility files"
8. Open savedpositions.txt
9. Copy the line(s) you have in that file
10. Paste it to your gamemode / change vehicle IDs if needed
11. Compile

To remove vehicles, search for "AddStaticVehicle" or "CreateVehicle" in your script

Hope I understood what you meant, and hope you understood what I meant