You can change any of the key settings!

Go to Options > Settings > Controls and click on the Buttons/Keys tab. Make sure that the Event category is set to All events. Now scroll down to the commands that are using the keys you want to use, select the "event" Ailerons (bank left), and press the Delete key assignment button. Do the same for Ailerons (bank right), Throttle (increase) and Throttle (decrease).

Now the keys are no longer set to do the left/right turns, or throttle up/down, and they are free to be used for whatever you want to use them for.