I just added that section to the wiki as well. Although some patches have been proposed to accomplish this I believe there is a hold up on implementing them at this time. I believe gerritv has better knowledge of what the reason is.

In the mean time, it is best to change your display settings to stay lit while charging and to purchase a small car adapter to charge the tablet while in the car. You should probably do this anyway since the GPS tends to drain the batteries a lot quicker than normal.

Note that some car adapters might be able to provide enough juice to run the tablet but not necessarily enought to charge the battery. If you are purchasing a charger make sure you purchase one that is able to provide the same amount of power as the wall charger that comes with the tablet. Since Nokia used one of their standard power jacks it is possible to by a car adapter for a cell phone that doesn't have enough power to charge the battery (don't ask how I found this one out...). The tablet will think it's being charged and thus the display will stay lit but it will take a VERY long time to charge the battery or it might not charge at all.