Okay, I will give you a small tutorial.
1. Go to the area you want your skin to spawn into and type /s
2. Check out your Vice City folder and find a file named "vc-mp_saved_coords"
3. In there you will find the cords that you saved ingame.
4. Copy the cords and paste them in your "config.ini" file near other skin locations.
5. Now edit the first 2 zeros of the code (0 - Team color) (0 - Skin model)
6. Save the changes in your config.ini and you're done