Yes, if you hit the NAV button then the AP button.
Granted that the Nav/GPS mode switch is turned to GPS, or else that will not work.

To answer the querstion, simply open the GPS window and while in "map view" click the "Menu" button and use the horizontal arrows to switch "yes/no", and the vertical arrows to move up or down.
Then push "Enter"

The FS2002 GPS is a very basic one, and it cannot be programmed like the "Legs page" on an FMC, where you input the names of several wpts (or airways) and hence create a funcitoning flightplan. The MS GPS gets waypoint data from the flightplan you create in the "flightplan" menu, although, the GPS can be programmed to give you a direct route to a waypoint/airport.
I think mostly uses it as a "moving map" function, since the default MS planes has a very limited ND screen.
Hope this helps!