The only way I know to do this is to manually change a file named "Main_CharacterStats.txt" in the Campaign Folder (i.e.: Homefront).
You should take note of your current stats and after installing the full game you place them here:
Starting Credits := 200000
Base Attack Rating := 5
Base Defense Rating := 5
Base Negotiation := 0
Base Hull Regeneration Rate Per Second := 0.00
Base Armor Regeneration Rate Per Second := 0.00
Base Shields Regeneration Rate Per Second := 1.00
Base Energy Regeneration Rate Per Second := 1.00
Then you start a new Campaign (i.e.: Homefront) with all stats at the levels you specified.
Have fun.
