Write down the amount of credits you have just as you save your game.
 Open the savegame-file with a hex-editor.
 Search for the value of your credits.
 This value appears in  3 places in the file. Edit all 3 instances to
 something that satisfies your need (or greed !). Save the file then
 reload it into the game.
 Please note that this cheat is useless in the missions where you have
 no construction activities.

 By Temel Bahadir, temel.b@telia.com