I found this save on one of my disks from 2004, this is so you start the game with 6 million credits. If you have not already made a save you have to complete these folowing steps for the save to show up:
- Start a new game
- then go to a nearest station to save.
- Then exit to the main menu and load up this cheat save number x6.

If this one doesn't work there is the x9 version on this website.