POI gpx format icons


I have a Garmin Summit HC and I can load a poi (gpx) file ok when I have a bmp file with the same name. This loads the same icon for all POI's. However if I try to load one with the icon listed in the gpx (different icons for each POI) file all I get is the same icon (med city) instead of what i listed in the file. Can some tell me how to use the gpx format to load internal icons (one for each poi in the gpx file)???