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The process is the same as
editing the All-Star teams in so far as replacing and removing players.
However, I have left the original entry for Dwyane Wade in the NBA Live 08 roster update so you don't need to worry about creating him. To add him back into the USA roster, open players.dbf with DB Commander, search for 3024 in the PLAYERID column and then scroll across to the TEAM column. Change his value from 32 to 79 and his ROSTERPOS value from 2 to 12.
You can then close DB Commander, run the game and then re-load the rosters. Wade will now appear on the USA team and you can reorder the rosters accordingly to bring him into the active roster.