The first step is to change longitude and latitude to minutes.
If longitude and latitude are in degrees you need to make a math formula where you multiply that signal with 60. And set the Timebase on "Async" and select the CANs latitude channel for the Channel, as seen on the picture below. Do the same for longitude.
If the channels are already in minutes skip the first part and go to this one.
The second step is to tell Dewesoft this are GPS signals to do this go to channels, click on setup and set the type GPS X for longitude and GPS Y for latitude.
Now you can select this channels in the GPS visual control.