Make your entity a specialization of the GoogleMaps.Location entity and make use of that specific address attribute in there. On this GoogleMaps.Location entity an eventhandler (BCo_Location) is available that will geocode your address when committing the Location object.
After that, configure the Google Maps widget to be populated with your entity and chose the latitude and longitude attributes that your entity inherits from it's generalizaration, the GoogleMaps.Location entity.