I hope you have a pen and paper.

1-Key in ignition (car on or position 1, doesn't make a difference).

2-Press the menu button on your navigation screen.

3-Select the settings menu.

4-In the settings menu (where you set up time/date, etc...) hold the menu button for about 15 to 20 seconds.

5-Step 4 will take you to a seperate menu. In this new menu you need to scroll all the way to the bottom of the screen until you see an option called perspective. Select it.
6-In this perspective sub menu you have the option to turn it on or off. Set it to on and the perspective option should show up just like it is in the picture.


Of course this is assuming that you have V28 or a modified ealier version installed.
EDIT: Just read the part where you said you had V28 installed.


Hope this helps,
Best of luck.