_____________________________________________
How to make an offline profile work as online profile
_____________________________________________
If you started with an offline savegame but want to make it work online, you could try the following steps. It's no guarantee that this will work for you, but it did for some people.
The TDU savegame is located in "My Documents" in a folder called "Test Drive Unlimited". Inside this, there is a folder called "savegame". Back it up somewhere.
After you made a backup, delete the savegame folder. Then start up the game and create a new online game with the exactly the same ingame name. Go through the tutorial and buy your first car and first house. Make sure you are online and once you are, quit the game and it will save your current progress.
Now go back to the TDU save folder and open up the new savegame folder that was created with your profile name. Example: Test Drive Unlimited\savegame\BBusterNL\playersave.
In that folder there will be two files: "playersave" and "commondt.sav"
Open the old savegame you made a backup of earlier and which contains your old offline profile. There are two folders, named "playersave" and "playersave2". Open the most recent one and copy the playersave file to your newly created savegame. Let it overwrite the current file.
Now restart the game, hit continue and now you should be online and have all your cars and progress.